# Planted Tanks > Fertilisation and Algae >  how to stop green spot algae

## cravy

How can i stop green spot algae? any type of fishes / shrimps eat them ? or what can i do to the water to stop them ?

They turned into black color spots on the leaf of the plants after some time....

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## hwchoy

shorten your lighting hours, don't let the sun shine on the tank, use green wool (or something softer so as not to scratch your glass). those black things are a different algae.

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## cravy

so what are the black spots on my plants... there are alot green spot on my tank n plants.

How can i stop them ? any fishes or shrimps eat them ?

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## hwchoy

all different kinds of algae, all because of nutrient imbalance. you can search around the forum as there has been a lot of discussions on algae. on the other hand, algae is a part of nature, so some algae is natural and cannot be completely avoided. As long as it doesn't go out of control.

First thing you can try (besides the light thing) is NOT to overfeed your fish. Too many people tend to do that, fishes do not need three square meals a day [: :Smile: ]

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## Allen_1971

Lately I've had greater success in the control of green spot algae. Interestingly, the solution lay in increasing my dosage of fertilizers. 

Originally, I used to do a 40ml dosage of TMG during a water change. However, it became apparent that green spot would break out around the 6th day of the week. So I started experimenting. Currently, I add a second booster 10ml of TMG aroud the 3rd-4th day after the water change. This seems to help inhibit the growth of the spot algae. And while I can't claim to have 100% gotten rid of it, its growth rate is reduced substantially.

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## FND

> ----------------
> On 6/30/2003 1:43:00 PM 
> 
> Lately I've had greater success in the control of green spot algae. Interestingly, the solution lay in increasing my dosage of fertilizers. 
> 
> Originally, I used to do a 40ml dosage of TMG during a water change. However, it became apparent that green spot would break out around the 6th day of the week. So I started experimenting. Currently, I add a second booster 10ml of TMG aroud the 3rd-4th day after the water change. This seems to help inhibit the growth of the spot algae. And while I can't claim to have 100% gotten rid of it, its growth rate is reduced substantially.
> ----------------


Hi All,

I like to support the statement by Allen. I believed my new routine helped to minimise the growth of spot algae. I changed my water every 2 weeks, normally about 40-50%. Always thought that the green spot algae will be a mainstay for me as I have my tank in the balcony. There is some morning sun for a couple of hours. The routine comes about because I have the black spot on my amazon sword

Since I have fan on 24 hours, I have to top-up about 3l of water every alternate day. Decided to change my fertilization routine, as I thought that the previous weekly routine is insufficient. I've been dosing 5ml of JBL Ferropol every water top-up for my 4ft tank. 

Outcome - I have little success with my Amazon Sword black spot on leave but this experiment solved the other problem, that is, green spot algae. :Wink:  

-FND-&amp;gt;

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## naturetan

For my case, I used to have lots of green spot algae on glass just before every water change a week. My dosage of PO4 helps me solve this problem. Now, I seldom find any on my glass every water change. Hope this helps for your case.

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## logan

> ----------------
> On 6/30/2003 6:59:12 PM 
> 
> For my case, I used to have lots of green spot algae on glass just before every water change a week. My dosage of PO4 helps me solve this problem. Now, I seldom find any on my glass every water change. Hope this helps for your case.
> ----------------


hi naturetan...well, i am a bit confused.I have read that adding extensive PO4 can lead to algae blooms. So, are you saying that you have decreased your PO4 addition or...?

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## naturetan

It depends on what you mean by &amp;quot;extensive&amp;quot;. Usually, your tank will have more algae problem if PO4 drop too low. The good range is 0.5ppm-1ppm. Slightly more is OK and will not hurt. It is usually too low that give problem, IMO. Depending on your bioload and tank condition, for my case, I dose 1ppm, 2X per week to prevent it from running low. Any excess will be removed through water changes.

The idea is to keep your tank nutrients within a good range or even slightly more, and your plants will absorb nutrients well enough to grow very healthy.

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## PeterGwee

Do note that initial dosing of all the necessary ferts might cause the algae to grow better as plants are probably in bad shape and needs time to bounce back. In the mean time, just keep up with dosing and manual removal of algae and do not fret and point fingers at the fertilizer dosing. Algae have lower biomass and hence needs only micro amount to survive whereas plants need much more..(limiting nutrients seems to work on algae as they don't have much storage capacity of nutrients and will get hurt real fast whereas plants hang on much longer...but do note that algae bounce back real quick and plants take much longer when it is stunted.)...The key is to grow plants and the only way is to give them what they want..CO2,N,P,K,Mg,Ca,traces..thats it.[ :Grin: ]

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## logan

Thanks naturetan and PeterGwee.....

Hmmm...what you guys are saying is this: give the plants all the nutrients that they need, but just don't over do it.
Am i right?

The topic of fertilising has been very confusing for me...I am going to start a 3ft planted tank very very soon. Could you guys kindly give me a reccommendation of fertilisers to buy, liquid or otherwise? Thanks again.

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## Plantbrain

Plants don't grow=&amp;gt; algae will.

The focus of a planted tank is healthy growing plants. 
Give the plants what they need to grow well. 

There's a great deal of old myths surrounding planted tanks. I suppose there will be for a few more years yet.

I had high PO4 in my tap water for years and consistenly produced and grew more species of plants than many other folks in the same area. No algae either and I did huge water changes weekly after which the plants would pearl like mad. 

I've had high PO4 for over a decade now. Still no algae that I can attribute to PO4 using high quality Lamott test kits etc.

Dr Mallick's sells, the fert's, they are cheap and easy to use.

A 3 ft tank with .7w/l would have a routine perhaps like this if it contained 150 liters or so:

1/3 teaspoon KNO3 2-3x a week
1/3 teaspoon K2SO4 once a week after wtaer change only
7-8 mls of traces(TMG/Flourish etc) 2-3x a week
KH2PO4 2-3 rice grain's worth 3x a week or so.

CO2 cranked high. Lots of plants, 50% weekly water changes, good regular pruning, Amano shrimp(maybe 30-50) etc

It's easy and become routine quick.


Regards, 
Tom Barr

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