# Planted Tanks > Plant Talk >  Placement of CO2 drop checker

## mercur1al

Came across many interesting threads on how to properly use a drop checker, but none on the actual placement of CO2 drop checkers.

Given my own tank as an example, where would you place the drop checker?

I'm using an inline diffuser, the Co2 is coming out from my lily pipe outlet.

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## Urban Aquaria

I usually place my drop checkers just behind the outflow pipe (like at D in the photo)... reason being thats the area with lowest flow and the place where the Co2 will be the last to reach, so the measurements would likely show the "minimum" average Co2 levels.

Least preference will be at areas in the path of the outflow, especially where the tiny Co2 bubbles can be visibly seen flowing around, as bubbles will tend to float into the drop checker and result in measurements showing higher Co2 levels than it actually is.

Anyways, the drop checker can be attached at different areas to check for dead spots too, thats one of the useful functions of a drop checker.

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## milk_vanilla

Near pale plants, to give you guarantee it's not caused by co2.

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## Ipit

I use 2 drop checkers. My returns are from the back of the tanks so I place them on the left and right of the tanks. 
Visually ugly but I just want to make sure sufficient Co2 is supplied  :Razz: 

Sent from my 2013023 using Tapatalk

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## peanut88

I also use a drop checker and yesterday I just change the solution in it.

After 2 hours, I went to check on the color of the drop checker solution.
I GOT A SHOCK ! The entire solution inside the drop chdcker disappeared.

I immediately removed it from the tank and check on all the fishes. Luckily all are well.

I check the drop checker for leak and it was not leaking at all. Where did the solution went ? ! 
There are only 2 possiblities - it somehow leak out or evaporated.

Will the solution harm any fish or plants if it was leaked into the tank ?

I am puzzled indeed ? ? ? ! ! !  :Surprised:

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## Urban Aquaria

> I also use a drop checker and yesterday I just change the solution in it.
> 
> After 2 hours, I went to check on the color of the drop checker solution.
> I GOT A SHOCK ! The entire solution inside the drop chdcker disappeared.
> 
> I immediately removed it from the tank and check on all the fishes. Luckily all are well.
> 
> I check the drop checker for leak and it was not leaking at all. Where did the solution went ? ! 
> There are only 2 possiblities - it somehow leak out or evaporated.
> ...


What does your drop checker look like? And when you removed the empty drop checker from the tank, did it still have an air pocket in it? or was it flooded with the tank water?

Anyways, drop checker solutions are generally harmless if leaked in very small amounts into tanks (unless your tank water volume is really tiny until it actually tints the water).

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## Ipit

i experienced same thing before, i was using the conde shape plastic checker. the base is hollow, liquid is filled up in the cone and then need to attach the base to the cone. i didnt connect properly so the liquid came out.

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## peanut88

> What does your drop checker look like? And when you removed the empty drop checker from the tank, did it still have an air pocket in it? or was it flooded with the tank water?
> 
> Anyways, drop checker solutions are generally harmless if leaked in very small amounts into tanks (unless your tank water volume is really tiny until it actually tints the water).


Mine is like this one. The curious thing is that I made sure it was snap tight shut before I put it in.
Was not aware if there was any air pocket or not.

http://www.ebay.com.sg/itm/Up-Aqua-a...-/330717830291

I think I will have to get another safer type of drop checker like this one.
http://www.ebay.co.uk/bhp/co2-drop-checker

 :Surprised:

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## Urban Aquaria

> Mine is like this one. The curious thing is that I made sure it was snap tight shut before I put it in.
> Was not aware if there was any air pocket or not.
> 
> http://www.ebay.com.sg/itm/Up-Aqua-a...-/330717830291


Yeah, those plastic drop checkers with snap on indicator compartment covers do have a possibility of leaking due to a loose o-ring or connection.




> I think I will have to get another safer type of drop checker like this one.
> http://www.ebay.co.uk/bhp/co2-drop-checker


Yes, those fully sealed drop checkers are definitely more secure.

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## Bieffe

Will buy 1 today and place it like u have suggested. Your rational is Plausible.

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## Bieffe

Do we use reference liquid or just take water?
Aiyo all no stock. Saw 1 but so big.

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## Bieffe

Not to mention they vary quite a bit in size. Bigger better or no diff...sure looks ugly.

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## Urban Aquaria

> Do we use reference liquid or just take water?
> Aiyo all no stock. Saw 1 but so big.


You usually have to use 4dkh reference liquid to mix with the indicator reagent to create the indicator solution... or just buy the pre-mixed indicator solution, no need to mix can use directly.

The common glass drop checker designs do usually look abit over-sized in smaller tanks.

There are other designs though, and one of them which i use in all my tanks now is a hang-on drop checker, it works the same as the common in-tank drop checkers, but is kept mostly outside of the tank (and doesn't get covered in algae), looks like this:



Photo from eBay.

Here is a search link to the various sellers on eBay: http://www.ebay.com.sg/sch/i.html?_from=R40&_trksid=p2047675.m570.l1313&_nkw=hang+on+drop+checker&_sacat=0

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## Bieffe

Cool but it position is limited.
I cannot have the fun and stress of choosing position A B C D E F G...hahah.
How long to place the co2 indicator inside?
And when to chnage the liquid?

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## Urban Aquaria

> Cool but it position is limited.
> I cannot have the fun and stress of choosing position A B C D E F G...hahah.
> How long to place the co2 indicator inside?
> And when to chnage the liquid?


Yeah, its more of a long term placement type device, mainly for those who want less items cluttering up their aquascapes (and one less item attracting algae too).

Usually once you dial in the right amount of Co2 injection and finish testing the Co2 distribution with normal in-tank drop checkers... then can replace with those hang-on ones for longer term monitoring.

Most people just leave the drop checkers in or on their tanks permanently, since it will constantly provide a visual indication of the approximate Co2 levels. If there are odd color changes, then you can quickly act on it.

The indicator liquid can usually last for months (or until it evaporates).

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## peanut88

May get this more precise CO2 meter when it is available.  :Smile: 

https://www.kickstarter.com/projects...-for-aquariums

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## Bieffe

Did u get this oco darn good device. If seloniod makers can in cooperate this into their design at low cost this will be fantastic!

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