# Killies Import > Planted Tanks >  CO2 Injection/Diffusion

## SQUEAK

Hello all,

It has been a while since I've really done anything constructive, but I have a question to those of you who use CO2 injection systems. First, how I do it, and have done it:

First method: simply bubbling CO2 into tank using yeast/sugar. Most CO2 is lost through this system, not very effective. Improved by using a passive diffusion bell, however I have read that passive CO2 diffusion is not very efficient, and at most will obtain a concentration of approximately 10 ppm.

Now, I use essentially the same system, but with a small powerhead 'blowing' water past the bottom of the diffusion bell, to catch a small eddie current within the bell, and hopefully the faster moving water will help diffuse in some more CO2.

I have read, but not tried, of some people rotating the output of the powerhead to point downwards into a short tube, and then to bubble CO2 into the tube (so the bubbles will be trying to 'move' opposite to the direction of water flow). I obtained this idea from the articles section of petfish.net/articles.

I'm interested to know how folks on this forum regulate CO2 levels in their tank, if they do inject CO2 at all. My plant experience (and horticultural abilities in general) is rather poor, unfortunately - I could kill a rock  :Very Happy: . Anyways, just curious - I hope to some day achieve the level of planting that some folks on this site are able to achieve - my tanks are mostly composition of a lot of stem plants, giving it a somewhat 'weedy' look.

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## SQUEAK

I just noticed in another thread that Freddy (user fc) http://www.killies.com/forum/viewtopic.php?t=3431 suggests that using a ceramic diffuser is a bad idea with DIY set ups, I guess the pressure will become too much - it is a good thing I read that, I literally have a ceramic diffuser being mailed to me right now. I will have to avoid using that.

Cameron, or anyone who might recognize the spiral diffuser on his tank, could you let me know how well that diffuser worked for you, and where you obtained it from? It looks like it would be an efficient way to keep the CO2 in the system for an extended period of time, however I haven't found any spiraling diffusers without the ceramic plate. Sorry, I would normally private message for this, but I do not know your user name. Thank you in advance for your time.

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## Desmond

Hi Peter,

For me, I am also using DIY CO2. My reactor bottle is connected to a bell in which my outlet pipe is slightly directed towards it so that the water will get mixed with the CO2 and it is working fine. 

I bought a spiral with a ceramic diffuser too, but I am unsure of whether to use it. Not quite clear with what Freddy mentioned regarding DIY CO2 having only a low pressure. Is it due to the low pressure, the gas will not be able to escape through the ceramic  :Question:  Someone please enlighten me  :Exclamation:   :Rolling Eyes:

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## SQUEAK

Desmond,

It sounds like we have similar setups. I think I have seen the type you are referring to - is it possible to pop the ceramic disk out?

My guess would be that the pressure in the soda bottle (or whatever bottle you happen to use) would become greater and greater, as the ceramic disk would diffuse slowly. The increase of pressure will eventually lead to a rupture, either in the cap itself (warping of the cap), or via the bottle exploding - the worst case. A pressurized CO2 system has to be stored in metals that are far more resistant to the pressure, and won't explode.

I hope that makes sense, it is very late at night for me, so my writing may not be very clear.

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## FC

> I bought a spiral with a ceramic diffuser too, but I am unsure of whether to use it.


Hi Desmond,
The home-made DIY CO2 does not have enough pressure because the CO2 is produced by the naturally fermentation process - through breath of the micro-organsm which are consuming the glucose of the sugar solution. The pressure you get are the sum of their "lungs" pressures.

Your lung's pressure is certainly stronger than theirs, so do this experiment: Try blowing the spiral diffuser. You would get a feel of the pressure needed for the air to pass through the ceramic coin.

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## FC

> Cameron, or anyone who might recognize the spiral diffuser on his tank, could you let me know how well that diffuser worked for you, and where you obtained it from?


Hi Peter,
Cameron's user name is "Happy Camper".
Spiral (and ladder) diffuser is quite efficient, about 70% compare to a good reactor. If you look closer to a proper design/made spiral diffuser, it has a small opening at the base to allow water in. As the CO2 bubbles rise up throught the spiral, it create a vacuum effect at the bottom, thereby sucking in fresh water. From here, the CO2 works naturally in the spiral, mixing and dissolving itself with the continuous in-flow of fresh water.

*KL*, if you are reading this, can you kindly post the pic of your spiral diffuser? Zoom in to the base of the diffuser to show the water inlet part. Thanks!

Note that the spiral used with ceramic are gimmick. There is no hole at the base. The spiral there has no role in helping to dissolve the CO2 as no water is introduced in the process.

Since you have a small pump, you may also consider using reactor (internal or external), see this thread for example of reactor http://www.killies.com/forum/viewtopic.php?t=3300.

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## SQUEAK

Well, that makes for a rather silly diffuser (the ceramic ones). I suppose then the only advantage that has to straight bubbling throughout is that the surface area is massively increased (in theory). I guess I need to look for one of these reactors, or something similar to it. Thanks for your help Freddy!

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## Desmond

Hmm. That means i wasted my money twice! I broke the first one and got another ceramic diffuser.  :Crying:  Is it possible to remove the ceramic cap and probably i will place a bell over it to trap the CO2? And secondly, if i am using pressurized CO2, will i be able to use the ceramic diffuser?

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## FC

> I suppose then the only advantage that has to straight bubbling throughout is that the surface area is massively increased (in theory).


Yes, exactly, it simply break up the incoming CO2 into multiple tiny bubbles, thereby increasing the surface area/contact to the aquarium water for better dissolve rate.

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## FC

> Is it possible to remove the ceramic cap and probably i will place a bell over it to trap the CO2?
> And secondly, if i am using pressurized CO2, will i be able to use the ceramic diffuser?


It is useless once you removed the ceramic, the spiral (of this type) does not help in dissolving the CO2 at all. It will be just a coiled tube, look at it again.
Certainly, ceramic diffusers are made sepcifically for pressurised CO2 tank only.

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## Happy Camper

Hi Peter

The spiral diffuser in my tank was sent over by a very kind hobbyist from overseas, I can't divulge his identity as I doubt he would be too impressed with numerous requests for co2 diffusers, sorry. I see that you are in America so it should not be too difficult for you to source these diffusers (ask someone over at aquaticplantcentral.com). They do seem to work quite well with the DIY co2 setup, the plants have no visible pearling but growth is slow and healthy and looking good. This is a nice diffuser to use on a moderately lit tank, for high light you would need to go pressurised in my opinion. Also keep in mind that the diffuser has only been put into my tank a few weeks ago, all that growth has happened slowly over the past year or so using only low light and no co2 at all! All the plants are very easy to grow low light plants like Mosses, Anubias, Java ferns and Crypts. What I'm trying to say is that you don't *need* the co2 in order to have a semi-decent looking planted tank.

I have messed around with diy co2 for quite a while now and I think the best way of diffusing DIY co2 is with Tom Barrs DIY diffuser, you can build one fairly cheaply. You need a small powerhead, and a gravel vacuum can be easily manipulated into the container that holds the co2, this gets your co2 levels up high but not stable. The method works but is erratic IMO, as the co2 levels are constantly fluctuating! Your experience may be different but you should try and build one just to see what it does for your plant growth.

I found these 2 links for you to give you a better idea of what I'm talking about, if anyone else has decent links to Toms DIY diffuser please post them for Peter to see.

http://www.barrreport.com/articles/7...ri-design.html

http://www.barrreport.com/articles/7...ri-design.html

Hope that helps a bit.

Kind regards
Cameron James

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## SQUEAK

Cameron,

I'm very grateful for your post, it has helped me out tremendously - those links were essentially exactly what I need. I'm still trying to figure out what one of the lines is (on the right side, there's a line running which Tom calls the 'Venturi Loop' - I haven't discovered the purpose, or setup, of this loop... is it drawing the water back into the powerhead from the outlet pipe?).

I understand that you cannot divulge the name of the supplier of the spiral diffuser, thank you for letting me know  :Smile: . I imagine an item like that would draw a lot of attention.

Believe it or not, I cannot grow a java fern for the life of me. This would be a 10 gallon tank, with 30 watts of light on it (I can run it at either 15W, or 30W as I choose), right now with a passive CO2 diffusion. The plant just doesn't want to adhere to the rock! I have grown some other plants (apparently, more difficult plants) without a ton of difficulty, but I've failed with java ferns, java moss (yes, I'm quite serious), and amazon swords. Very embarrasing.

Plants I have been able to grow include: rotala rotundifolia, Althernanthera Reineckii, water wisteria (did well for a while, then suddenly the stems just simply rotted...), Myriophillum (still looking for the actual name), and a few others I can't identify. Now, I'm trying to grow some crypts and anubias, but it is the first time at it - we'll see how successful (or unsuccessful) I am. Just to give you an idea of my plant experience - I'm rambling a bit.

I do have a question though: what does pearling refer to? I have heard the term tossed around a few times, and I think it is either a gaseous emission by the plants (collecting on the leaves), or just bubbles that are in the tank that become 'adhered' to the plants. I'm a bit unclear as to what it is, and also what pearling would indicate for plants.

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## timebomb

> *KL*, if you are reading this, can you kindly post the pic of your spiral diffuser?


Sure, Freddy. Actually, there's already a picture of the spiral diffuser in this forum. Here it is:



At the lower end is the water inlet that Freddy spoke of. The way the diffuser works, you pump your CO2 down the long tube that's in the middle of the spirals. The bubble makes a U-turn when it reaches the bottom and rises through the spirals. The spirals slow the ascent of the bubble, thereby allowing time for the bubble to be absorbed by the water. You can actually see this happening because the bubble gets smaller as it rises.

Loh K L

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## timebomb

> I do have a question though: what does pearling refer to?


Pearling, to an aquatic gardener, would be when the plants give out oxygen bubbles. It's actually photosynthesis in process. Some plants are known to pearl more than others. _Riccia fluitans_ is the champion pearler of them all, I think.



Loh K L

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## SQUEAK

Loh K L,

Thank you for the pictures, I did not quite understand how the spiral diffusers with the water inlet worked - that clarifies it quite a bit. It might be possible to modify the ones without the water inlet to make a small hole, but I wouldn't recommend anyone without a lot of experience in glass (and knowing what type of glass it is), to even think of attempting it. Glass can be very dangerous if mishandled.

Thank you for the picture on pearling, I have never seen that happen in a tank before. I forgot to add riccia to the plants that I have no luck with  :Laughing: .

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## Happy Camper

Hey Peter

The Venturi loop is not absolutely necessary (IMO) if you don't want to build it into your system. Most powerheads come with a small bit of airline that fits into the top of the powerhead, this usually sits just above the water surface and sucks in atmospheric air and then spits it back into the water as small diffused bubbles. On Toms Reactor the airline does not go to the surface but rather back into the co2 holder where it draws co2 bubbles back into the powerhead and spits them out again, so you apparently this is supposed to dissolve the co2 even more and make it more effective.

Java ferns can be funny that way, I have them in all my tanks and some do much better than others, I suppose it depends on the condition of the setup it's in. In your 10 gallon I would recommend to go for 30w instead of 15. Do you dose any fertilisers into your tank? If you have a good fishload then you can safely get away with only dosing trace ferts and a good water change once in a while.

Loh K L's picture of the pearling Riccia is the perfect example of plant pearling. This usually happens in fairly high light setups when the co2 levels are high. What happens is that the water column becomes saturated with gas (co2 and oxygen) until it cannot hold any more. Thus, instead of the oxygen from the plants dissolving in the water they appear on plant leaves as bubbles. Sometimes they even make tiny chains of bubbles (like you see in a champaigne glass). This is indicative that the photosysnthesis process is 'going like a boeing'  :Smile:  Although it is a good indicator that the plants are doing well you will probably not see much of this happening within low light setups, even though the plants are doing just as well, just slower growth.

Good luck with your co2 ventures, I hope you come right.

Regards
Cam

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## SQUEAK

Crazy idea, but what that glass diffuser you have reminds me of is a childrens drinking straw. They are often made with a spiral shape, so the child can see the drink rise through the straw, sort of like this:



I've occasionally seen these sorts of straws with a much longer spiral to them. Clip the tops and bottoms of the straw, and fuse a few of them together with a soldering iron, or silicon glue. A small hole right above the bottom of the straw (attach an air line to the bottom of the straw) to draw in the water as the CO2 moves up the line. In theory, with some careful work, the spiral could actually be very long.

Loh K L, Freddy, or anyone with a diffuser similar to the one in Loh K L's picture, do you know approximately what the internal diamter of the diffuser is? My first concern with a straw is that the bubbles are not going to move through the straw very well (adhesion will cause it to stick to the sides, for instance), and I think the spiral straws in particular have a very small internal diameter.

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## SQUEAK

Cameron,

I'll keep it at 30W then. As for the tank itself, it is a 10 gallon tank, with 2 _fundulopanchax sjoestedi_ living in it, and one Ramshorn snail for the cleanup duty (unfortunately, I'm constantly fighting with a rather nasty blue-green 'algae' build up - although it's really a cyanobacteria I think). Not a heavy bioload, but I'm sure having problems with that algae!

The explanation for the Venturi loop makes perfect sense now - thank you for taking the time to explain it. I do use a fertilizer, and water changes weekly of ~20%, and twice a week just cleaning out that dratted slime. For reference, it is a liquid fertilizer called Flourish (made by Seachem), 1ml per week, directly after the water change.

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## Happy Camper

The cyano you're referring to is indicative of unbalance in your tank, and I can see why. Cyano occurs in planted setups when the ratio between N and P becomes unbalanced. Usually the plants use up all the Nitrates and leave loads of P (Phosphate) in the water thus resulting in Cyanobacteria. This would explain why your plants are not doing too well (as there are no nutrients for them to munch on). It ruined a couple of my tanks before I eventually managed to erradicate it. It's actually quite easy to get rid of:

I have'nt tried this on any of my Killi setups so you may want to remove the fish before going ahead with this. Basically you need to give the tank a blackout. Do a nice water change, remove and siphon as much of the cyano as you can from the tank. Add back the new water. Keep the filter going. You need to wrap up the tank with old blankets, towels or plastic sheeting, there should be absolutely no light getting into the tank whatsoever. Keep it like this for three days. Do not peek inside during this stage, not even to feed the fish. After 3 days remove the covers, do another small water change, clean out the filter a bit and your tank should be pretty much free of Cyano.

Your fishload is low and is not enough to sustain good plant growth, you will need to think about adding Macro fertilisers to the tank, Nitrate, Pottassium and Phosphate would be a good start, Seachem covers all of these and should be available to you if you're using Flourish already (what exactly is in Flourish?)

Wait until you've sorted out the cyano and nutrient issues before adding the extra light. Adding extra light now will just make it much worse.

Good luck.

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## SQUEAK

Cameron,

The listing of Flourish is very large.

Nitrogen: .04%
Phosphate .01%
Potash: .06%
Calcium: .17%
magnesium .11%
sulfur: .277%
boron: .001%
bromine: .0001%
Chloride: 1.15%
Cobalt: .00004%
Copper .0001%
Iodine .3886%
Iron: .3886%
Manganese: .0125%
Molybdenum: .0015%
Nickel: .00036%
Rubidium: .0001%
Sodium: .0743%
Tin: .000030%
Vanadium: .00003 %
Zinc: .0004%
Arginine: .016%
glutamate: .09%
lysine: .03%
tyrosine: .019%
choline: .0004%
Inositol: .0011%
Biotin: .0004%
Niacin: .025%
Pantothenate: .007%
Riboflavin: .002%
Thiamine: .002%
Vitamin B12: .00009%
Vitamin C: 1.0%

Whew! That was a bit of strain on the eyes... I do recognize the names that you are mentioning, and yes they are available to me. I actually thought that there might have been too much of a bioload on the tank (as snails can be pretty messy little guys). I have actually been running the tank at 30W for a while now, so it would actually be removing part of the light.

I do have a smaller 5.5 gallon tank (very heavily planted) that actually does well with plants - I can grow plants in there that I completely fail with in other tanks, and I can't even figure out what I'm doing right  :Very Happy: . I've nicknamed it my plant hospital tank. I start plants out in there to establish root systems before moving them into my other two tanks, or plants that have gotten abused by fish.

That tank functions too well at times, it seems! There are no fish living in it, just a pair of snails. Blacking out the tank for a few days is a viable option, although my 5 gallon tank might be a bit cramped for the pair of killifish. Would it be at all helpful if I posted a couple picture (warning, they will be low quality) of the tanks, so you get a better idea of what I have been growing?

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## Happy Camper

A picture says a thousand words, post them  :Smile: 

I'm not a plant Guru, I'm merely giving you pointers to stuff I have experienced in the past. Flourish sounds like it has everything in it, in this case I would say that you've perhaps been dosing too little. If you dose your tank so that the Nitrate level is close to 10ppm then you should be good to grow plants. 

I'll wait to see the pics before making anymore comments in case I'm giving you the wrong advice.  :Laughing:

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## SQUEAK

Cameron,

I will divide this into two posts, so it is easy to know what is in what tank. The first post will contain my success tank. It is a 5.5 gallon tank, with 10 watt fluorescent bulb, with no algae problems to speak of. The air line you see running down is how I diffuse CO2 into this tank (it gets trapped underneath the rock.

Inhabitants: 2 ramshorns snails.

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## SQUEAK

Next tank:

10 gallon tank, has blue-green algae in it. 2 _fundulopanchax sjoestedi_, male and a female. I made a mistake earlier - there are 2 adult ramshorns in there, and I am constantly picking out the babies. As you can see, the planting is far more sparse, and consists heavily of stem plants (unfortunately), giving it a somewhat weedy look. The suction cup/green thing on the front of the tank is how I currently diffuse CO2 into this tank. You may also note some plants at the top. Those are actually stem plants (rotala sp) that have come loose. I took a bunch of cuttings recently from my 5.5 gallon tank and planted them, but they keep floating up! I haven't had a chance to re-plant them yet.

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## SQUEAK

Things to see:

5.5 gallon tank: there is a big clump of java moss on the right hand side - that is not the clump I killed  :Laughing: . However, it has a small infection of blue-green algae to it, and I didn't want to move it over (although I suppose since I already have it...). That's the only thing in there that does have the algae. The photos here really don't do justice to the 5.5 gallon tank, the depth perception has been lost, which gives it a very 2-D view, and looks more crowded than it actually is.

In the 10 gallon tank, if you look on the right hand side, you'll really see the blue green algae (you'll probably notice that this tank does really look more barren then the other tank... design is not my forte).

Cameron, you may know the answer to this. Between solid minerals such as plant tabs (iron tabs and the like), and liquid formulas (like Flourish Excel), is there a preferred one to use? I was never very clear if there was any particular difference between them, other than the ingredients. Sorry for picking your brain clean here!

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## Happy Camper

Hi Peter

Nice tanks  :Smile: 

I stand by my previous advice, do a black out, add more nutrients and see what happens. As I said before I'm not sure how well the Killies will handle the blackout so you may want to move them to your 5 gallon, they should be ok in there for only 3 days. I would drip them before moving them to the other setup just in case. I certainly would not want you to lose any fish during this process so please use your own discretion. The blackout method works like a charm, you can read various folks comments about it all over the net, just google 'cyano' and 'blackout' for many hits.

Regards
Cam

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## SQUEAK

Cameron,

Thank you, it is much appreciated  :Smile: . I'm trying to lose the rather 'weedy' looking aspect of the 10 gallon tank, however I try not to change the 5.5 gallon tank, as it does well for some reason. Tank design is a very odd thing - if I get it right, I get it right by chance  :Rolling Eyes: .

This weekend, I will try doing that blackout. I have a three day weekend coming up from university (just need to make it until 7PM tonight when classes finish!), and I can start getting a blackout ready.

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## Happy Camper

The only difference I can see from your descriptions about running the 2 tanks is that one (the 10 gallon) seems to be getting more attention from you than the 5 gallon. Are you always 'fiddling' with the 10 gallon, trying to make it perfect? Stop that  :Laughing:  The plants will be better adjusted if you leave them to grow in accordance to the tanks own metabolism, chopping and changing conditions is not good for plants, I know this all too well  :Opps:  

Once you've done the blackout and corrected conditions, plant the plants and leave the setup alone, the plants will grow just fine with little intervention from yourself. Oh, and don't forget to say 'hello you beautiful plants' every time you walk past the tank. Plants always enjoy a good chat, makes them feel at home :P 

I'd like to know how things work out for you so please post an update when the process is over.

Good luck

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## SQUEAK

The top two activities of an engineer: fiddling with anything and everything, and staying up all night doing work. I don't really do much to the plants but clean them off in the 10 gallon tank (rub the leaves to get the slime off), and occasionally to add new plants. I really shouldn't fiddle so much with that tank  :Opps: . I will update this when I have blacked out the tank, and waited a little while for the tank to recover from it. 

Back to work... class starts in two hours for me, I think I need a few 36 hour days to get everything done :P

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## Desmond

Thanks Loh K L for the picture on the diffuser. But I am now tempted to get a pressurized CO2 since it will do good on my plants!  :Smile:

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## chicknb

Peter, here is my advice based on my (short) experience with plants. 

You may use the power head to diffuse the CO2, I had that set-up a while ago with very good results. If you have an external filter, you may inject the CO2 to the inlet and have good results. I have it connected to my canister filter (Eden 501, equivalent to the Zoo Med Turtle Clean 501) in my 20 gal planted tank and so far I get very good results (most plants are pearling, including my Anubias nana) so if you have one I would suggest doing it that way, even if it is a power filter (like an Aquaclear) you may do it (I've also done it in the past). 

About the flourish, when I started using it I experienced some algae problems and had to reduce the dose. Now I dose weekly 4 mL of flourish, 1 planttab, 15 mL of peat extract, 7 mL of iron and trace elements, 1 mL of zeatins (plant hormones) and keep the pH at 6.6-6.8 with the CO2. I have flourite as substrate and only have some spot algae that gives the driftwood a nice look. I also keep an army of ramshorn and apple snails, 4 otocinclus and a bunch of cherry shrimp. I know that every aquarium is different but I just want to share my experience. 

Regards, 

Tony

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## SQUEAK

Hi Tony,

I could swear I've seen that exact picture of (what I believe) is _A. Mentos_ I've seen somewhere. Do you ever reside on petfish.net? Bit off topic, but I'm curious.

This 10 gallon tank is run by a sponge filter, so no luck with attaching it to the intake of this filter. However, that might work well for my 20 gallon tank! that is run with a hang on the back filter - for injecting the CO2, do you simply run the CO2 into the intake of the impeller, so that the bubbles hit the impeller blades?

Thank you for the listing of what you use; hard numbers like this are useful for figuring out what works for others  :Very Happy:

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## chicknb

Yes, you are right, I posted that picture on the petfish forum (as well as some others). It's my former Austrolebias alexandri Ceibas male.

About the CO2, yes, you just run a CO2 line to the intake of the filter and the impeller breaks the bubbles, it may make some noise but nothing really bad. At least it worked for me and it is still working for my brother in law (I gave him that 10 gal tank and filter). I will try to post a picture of my current setup so you may see how plants are growing. Meanwhile, I leave you this F. gardneri Akure picture. It does not show really the blue color it has because it depends on how the light strikes him. Anyway, I hope you like it.

Regards,

Tony

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## SQUEAK

Tony & all,

I certainly like the picture Tony - you have some excellent photography skills. Any time I even think about photographing my killifish, they immediately see me, and start ramming into the side of the tank wanting food (and in the case of anyone else being around the tank... well, they still want food).

As of 2/17/07, I've blacked out the tank. Black trash bag around the entire tank, with a blanket covering it - best I can do (I actually only own one blanket). The killifish have been moved into the 5 gallon tank, and seem to be adjusting just fine. I'll remove that blackout in 3-4 days, depending how busy I get. I'm going to be driving a lot this week, have to go home & later go for an interview  :Sad: . Have a great weekend all, and try not to do anything productive - it's bad for you.

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## chicknb

Peter, I don't have excellent photography skills, I just have enough patience to take dozens of pictures and select a decent one. It's not a joke, when I have time and patience, I take the camera (Nikon Coolpix L1) and try to take some decent shots of my shrimp, apple snails, and killis but very often they move while taking the picture. My opinion is to get a confortable chair and spend some time taking photos trying to understand the camera. By the way, my old pentax (forgot the model, maybe it was a Revio 30 or something) was much better to get good close-ups of my fish and it had manual focus control (which this Nikon lacks).

I hope you succeed against the algae.

Regards,

Tony

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## ed seeley

Hi guys,
I hope a few things I have learnt in my PT battles with Cyanobacteria (Blue green 'Algae', or BGA) will help. BGA will grow very well with low nutrients or higher ones, but phosphate isn't a cause. A lack of Nitrate will cause it though. However it has been seen by loads of people, myself included, that poor circulation will encourage it, hence why it's probably growing in the middle of your Java Moss. The only problem is your killis might not appreciate the faster flow!

Trying to add extra CO2 efficiently will help by boosting the plant growth. The problem is air powered foam filters and HOBs are two of the worst filters for outgassing CO2 from the water. You will have to a lot more to compensate. This is because they break the surface film and encourage gaseous exchange.

You CAN use good quality ceramic diffusers with DIY CO2, but you MUST make sure all your connections are very secure, otherwise BANG! Personally I'd stick to a ladder or spiral or use the power diffuser with a powerhead. Hagen do a good ladder that fits flat against the glass.

After your blackout I'd give the tank a really good clean and syphon out any debris or BGA that you see and the minute any more starts syphon it out. If you can up your flow rates and reduce the amount of surface disturbance (bit of a contradiction there, but if you lower the outlet you can do this).

BTW I use a CO2 reactor that's fitted to the return pipe of my external filter as it's one less thing in the tank and it takes no maintenance and does a very efficient job.

Hope some of this too long post helps!

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## SQUEAK

Ed,

Thank you for the tips. I'm still gleaning information from anything (it's all too much!). I did notice something for anyone who might be interested: Seachem Flourish states "Flourish does not contain nitrates or phosphates which can contribute to algae proliferation." With the low bioload that I do have, would it then make sense to supplement a nitrate source into the tank?

Also, after removing the covering, I found something that I didn't expect. The water had very thin (literally, almost too thin to notice) strands of green 'something', about a couple centimeters long. These were just floating free in the water, and I suspect that it would be the BGA that is dying off. Massive water change to try and get as much of it out, and I actually decided to try a second round of the blackout for another couple days, just to try and get the remaining BGA that appeared to have survived. The good news is that this appears to be a very successful method, and may save me a lot of headache  :Laughing: . Thank you to all who have contributed to this thread.

As for filtration methods, I'm really kind of stuck on what to do about that. Outgassing may just be a problem I will have. I don't know another good way that I can filter the water, without breaking the surface. However, I do have a powerhead; perhaps a cheap sponge attached to the intake of that would suffice? A lowered powerhead would not break the surface. A canister filter is, unfortunately, completely out of the question; I just don't have the space for a filter that size (I live in a 10'x15' room with 3 tanks - I'm always short on space).

I'm going to skip on using those ceramic diffusers. If something went bang, my apartment manager would be able to charge me so much in damages it would be ridiculous.

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## ed seeley

A lot of guys into PTs do regularly dose both Nitrates and Phosphates, but you need to couple it with high light, pressurised CO2 (or high DIY CO2) and 50% water changes so the nutrients don't build up.
Personally I think once you've given everything a good clean after your black out and upped the flow using the powerhead everything will settle down.
Get a ladder for your CO2, there's no back pressure generated by them at all, or just bubble the CO2 into your powerhead. The impellor will mash the bubbles up and blast them around the tank.
You can still use filters that disturb the water's surface, just bear in mind you may need to add more CO2 to compensate, maybe an extra bottle?

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## FC

> With the low bioload that I do have, would it then make sense to supplement a nitrate source into the tank?


In my opinion, keeping the water column in balance is the key to keep the algae away. My tank has been algae free many years and I can maintain that even without regular water change.

There are 3 ways to dose the water column:
1) dose directly to the water - for tank which contain rootless plants only
2) dose by injecting fertilizer into the gravel - for tank with rooted plants only
3) dose by both the above ways - for tank with both rootless and rooted plants.

Dosage depends on the light intensity:
1) Dose once a week for low to medium light (less than 0.8 watts per litre)
2) Dose twice a week for high light

If you do not want to mess with powders, try getting the Hagen NPK fertiliser (made in Canada), it is available here in Singapore and should also be in America. It is priced reasonably and has proper/balanced proportion of the NPK. See below thread:
http://www.hagen.com/usa/aquatic/pro...01076850020101

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## SQUEAK

Freddy,

I'm a bit unclear on one part. You mention injecting straight into the substrate (for absorbtion through a root system I would assume). Are you referring to using a substance that dissolves very slowly into the water (plant tabs, etc), or do you mean to inject a liquid solution directly into the substrate, using something like a syringe?

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## FC

Hi Peter,
Yes, I mean inject a liquid solution directly into the substrate, using a syringe. This will benifit the rooted plants directly. This is especially helpful for old setup where the base fertiliser has depleted.

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## SQUEAK

An interesting idea Freddy, I had never considered injecting solution straight into the substrate. However, wouldn't this mean that there would be simply concentrated 'pockets' of nutrients? I would think that water movement through the substrate is fairly minimal, at best. No more than using tablet form (or similar) I guess though...

It's worth a shot, right?  :Wink:  Thanks for the advice!

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## FC

Yes, there would be concentrated 'pockets' of nutrients. However, the concentrated solution will move out by diffusion and would be dissipated in about 2~3 weeks.
Tablet/solid form (so far) do not come in proper/balanced formulae.
I do use tablet/solid form but I use liquid much more to gain better control over what I provide to the plants.

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## SQUEAK

Hello all,

News is basically all good. After lifting the blackout from my tank, all the visible algae was gone or dead - it was a simple cleanup operation from that :P. Hooray! Also, I've adjusted my powerhead to blast into a little 'cup' with the CO2 in it, and turned off my air pump. There is now no break in the surface water (although there is a mild current agitation, no ripples).

I think I will attach a bit of foam to the intake of the powerhead to get two birds with one stone, filtration and the CO2 diffusion. The gas that is being placed into the 'cup' seems to dissolve at fast enough a rate that it doesn't spill out. Maybe it's just in my head, but there seems to be some more growth in just the last 3 days - lets hope, no?

Take a look at this little beauty just for fun, directly from the tank... _Hygrophilia Polysperma 'Rosanervig'_ (and no, those lines aren't photoshop  :Laughing: )



I'd like to thank everyone who has helped me with this problem - I will try to post pictures of it tomorrow evening. The tank is looking a lot better, now to figure out how to keep it that way  :Wink:  (and move back my killifish, who seem to have taken a real liking to their new tank...)

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## FC

Peter,
Congratulation!
The blackout is very helpful, indeed. I have a few suggestions:
Dissolving CO2
1) if possible, place the cup below mid height of the tank - to increase water pressure acting on the CO2.
2) I do not know how your filter foam looks like. If you can shape the foam such that the bottom form an inverted cup, you may consider bubbling the CO2 directly under the foam. The suction water flow there will help dissolve the CO2 and any undissolve ones will be suck into the pump and spray out like a mist. Note that the foam use should be coarse type.
Keep Algae Away
It is beneficial to dose the water column (use methods mentioned before) now.

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## SQUEAK

Freddy,

I will move the powerhead lower in the tank with the cup - that should solve that problem. I added a good dosage of Flourish into the water column after some cleaning, and injected it near the bases of plants (not directly into them, but a few inches away).

The filter foam is indeed the coarse type, however I don't think it would be feasible to make a bell out of it, the gas will just tend to pass through the openings in the cells, instead of getting trapped within. Right now, instead of the CO2 going into the powerhead itself to get 'mashed,' it empties into an inverted cup, and the powerhead directs a current through that. Seems to work, but time will tell I suppose.

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## FC

Hi Peter,
Typically, planted tank with fishes has insufficient Phosphate and Potassium, thereby, causing the plants in medium term (longer than 1 month) to suffer defficiency of these 2 elements. And weak plants invite algaes. Consider dosing, on top of Flourish, the NPK macro nutrients. If you do not like to mess with powders, try getting the newly available ready-mix Hagen NPK.
Note: If you do not change water frequently (like me), add also Magnesium and Calcium.
BTW, I hope you did change the water 100% after the blackout (to remove any stray algae).
Have fun!

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## timebomb

> Loh K L, Freddy, or anyone with a diffuser similar to the one in Loh K L's picture, do you know approximately what the internal diamter of the diffuser is? My first concern with a straw is that the bubbles are not going to move through the straw very well (adhesion will cause it to stick to the sides, for instance), and I think the spiral straws in particular have a very small internal diameter.


Peter, besides the diameter of the spirals, the length of the diffuser and the distances between the spirals are also important factors that will affect the performance of the diffuser. A couple of years ago, I needed a short spiralling diffuser, something that can fit into a low tank. The diffusers in the market were all too long to be of any use to me. I asked for help and was amazed when my friend in India sent me a couple of very short spiralling diffusers. He managed to find a glass-blower in Bangalore who could "blow" a shorter diffuser out of the taller model that was shown to him. I still have the diffusers with me and although they aren't very effective, it's still a great piece of work:



For the life of me, I can't figure out how the glass-blower did it but his diffuser even comes with studs where you can put in the suction cups. The Drop-Checker looks easy but how on earth did they create the spirals? They say India is a great country for out-sourcing various kinds of work. The fact that they can blow their own spiralling diffusers (and at a very low cost at that) is testimony to this  :Laughing:  

Loh K L

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## SQUEAK

> Hi Peter,
> Typically, planted tank with fishes has insufficient Phosphate and Potassium, thereby, causing the plants in medium term (longer than 1 month) to suffer defficiency of these 2 elements. And weak plants invite algaes. Consider dosing, on top of Flourish, the NPK macro nutrients. If you do not like to mess with powders, try getting the newly available ready-mix Hagen NPK.
> Note: If you do not change water frequently (like me), add also Magnesium and Calcium.
> BTW, I hope you did change the water 100% after the blackout (to remove any stray algae).
> Have fun!


Just clarification here Freddy,

You state NPK twice. In the first case, are you referring to the nutrients N P and K, or to the Hagen product 'NPK'? I understand in the second part that you are referring to the product, but I'm not clear in the first part as to which you refer to. If you are referring to the chemicals themselves, is there any desired 'ratio' to achieve with the chemicals, or is it more of the 'touch-and-go' style?

It looks like I will have to order the chemicals online. The only fish store near me has gone badly downhill these last two years, and has begun charging exhorbitant prices for sub-par equipment.

I did a large change directly after removing the blackout material (~75%), and since then have done another water change of about 30%, but not a water change of 100% all at once. Trouble brewing  :Laughing: ?

Loh K L,

I understand what you are saying, and have considered that - the diameter was mostly asked for out of curiousity. I am however, exhausted - I have been at campus the last 16 hours, and tomorrow isn't looking like a good day either!

Have a good night all.

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## FC

Hi Peter,

For all mentions of NPK, I meant Nitrogen, Phosphor and Potassium.
For Hagen NPK, see below pic which is self-explainatory.

Visit their website, there is dealer information for USA.
http://www.hagen.com/usa/aquatic/pro...01076850020101

With regards to desired ratio to achieve with these chemicals, I studied them hard long time ago. The problem is the knowledge was not stored in my brain's "hard disk" and it was not "backed up", it was in my "working memory" which was purged few years ago  :Laughing:  . BTW, the concentrations to keep are:
NO3 - 5~15 ppm
PO4 - 0.5~2.0 ppm
K - 5~15 ppm

*Key Points*
1) It is not critical to keep close/exact ratio but to maintain the individual nutrient within the above said range. This fact applies to all fertilisers.
2) For any plants to survive (to thrive will need more than these), sufficient concentration of all key nutrients are essential. The key nutrients include:
Micro - Fe, Mn, Cu, Zn, Mo, cobalt Co & B.
Macro - N, P, K, S, Ca, Mg, CO2 (carbon being the main building block).

*Others*
1) Temperature plays an important part in the metabolism of the plant.
2) Light is the driver and in some objectives, it is used as motivator.
3) Water flows provide/transport/dilute/diffuse nutrients and facilitates biological activities.

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## SQUEAK

Hello friends,

It has been a while since I posted - several weeks. The blackout was a rousing success, and I've implemented some of the suggestions made in this thread - as a result, I've had growths of almost _four times_ the original height of a couple species, most notably my _cabomba_ and _sessiflora_ species. Numerous other plants have been growing like mad, and even a couple runners being put out. A couple bits of algae have been starting to creep back in though... so fight, fight, fight against the recurrence of it :P.

Only problem... now that I have gotten my killifish into my 5.5 gallon tank, they don't want to get out! They are quite happy & settled into that tank now...

Finals start this week - so I don't have a lot of time to update. My most sincere of thanks to everyone who has helped out, or contributed their knowledge in some ways - I'm stunned every time I look at this tank.

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