# Help - Why is my water turning green?



## LHughes77

I am concerned with my tank and not sure what to do. About a month ago I noticed that the water in my tank was getting cloudy. I assumed this was due to a biological imbalance because we infested our tank with snails -- the kind that bury themselves in the gravel and you don't know until it is too late. Since then we've been working on evicting the snails (they relentless), but the tank water is turning green and I do not know why. I keep doing water changes but don't want to just continue doing that each day -- there is a cause and I need to figure it out. We've lost several fish, but the ones left seem to be doing just fine in the nasty green water (no, the tank is not near sunlight). I have removed a few remaining fish and put them in our other tank, but other than completely emptying this one, I am not sure how to eliminate the green murkiness.

Any help would be wonderful.....


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## iamntbatman

The snails shouldn't be a problem. If they're down in the gravel, it sounds like Malaysian trumpet snails. They won't harm your plants and will eat detritus in your gravel and keep it stirred for you. 

What sort of lighting do you have on the tank, and how long is it on per day? How often do you normally do water changes? Is the tank planted? How big is it, and what fish do you have in there? Green water usually comes from some sort of nutrient imbalance, so knowing all of this stuff will help figure out the cause of the problem.

Also, can you post your water parameters (ammonia, nitrite, nitrate)? Usually green water isn't enough to kill a fish, but it can indicate an ammonia spike which could be doing damage to your fish.


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## rocaquarium

Green water in an aquarium is nearly always caused by an free floating algae in the tank. The two things that can make them reproduce quickly enough to turn the water green are too much light and too much nutrients in the water.

The snail explosion may contribute to the problem. While it is true that they will eat the food in the tank that the fish miss they also produce waste after doing so. The uneaten food, fish and snail poop in the tank will all add the nutrients that the algae needs to grow.

Also, I am assuming that the algae has nothing to compete with. You rarely see green water in heavily planted tanks because the plants will use the nutrients before the algae does.

The easiest way to get rid of the green water is with massive water changes and be sure to vacuum the gravel well. Also, "blacking out" the tank by keeping the lights off and either placing a blanket over the tank or taping dark paper over the side panels will kill the algae (and any plants you may have in there).

While the tank is darkened you can put zuchini slices or spinach on the gravel. Many of the snails will climb on for a meal. Your can then pull the veggies out and get rid of snails. 

Going forward, make sure you are not over feeding your fish and don't allow more than 10-12 hours a day of light. Adding live plants to the tank will also help. Java ferns and java moss grow well with standard, low wattage aquarium lights.

On the plus side, the green water in your tank is very nutritious for young fish. If you are growing out any fry it can be used as food.


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## Pasfur

rocaquarium said:


> Green water in an aquarium is nearly always caused by an free floating algae in the tank. The two things that can make them reproduce quickly enough to turn the water green are too much light and too much nutrients in the water.
> 
> The snail explosion may contribute to the problem. While it is true that they will eat the food in the tank that the fish miss they also produce waste after doing so. The uneaten food, fish and snail poop in the tank will all add the nutrients that the algae needs to grow.
> 
> Also, I am assuming that the algae has nothing to compete with. You rarely see green water in heavily planted tanks because the plants will use the nutrients before the algae does.
> 
> The easiest way to get rid of the green water is with massive water changes and be sure to vacuum the gravel well. Also, "blacking out" the tank by keeping the lights off and either placing a blanket over the tank or taping dark paper over the side panels will kill the algae (and any plants you may have in there).
> 
> While the tank is darkened you can put zuchini slices or spinach on the gravel. Many of the snails will climb on for a meal. Your can then pull the veggies out and get rid of snails.
> 
> Going forward, make sure you are not over feeding your fish and don't allow more than 10-12 hours a day of light. Adding live plants to the tank will also help. Java ferns and java moss grow well with standard, low wattage aquarium lights.
> 
> On the plus side, the green water in your tank is very nutritious for young fish. If you are growing out any fry it can be used as food.


Great post. If my personal aquarium had this problem, I would apply this solution.

For the record, the "free floating algae" is actually a type of dynoflagillate. There has been a lot of controversial history surrounding this topic over the years, and it USUALLY leads to disagreements on internet threads. ;-)
The last published article I read on the topic actually suggested that the dynoflagillate could be air-born in nature, because laboratory studies showed a progression of green water from one tank to the next under controlled conditions. 

Anyhow, the details aren't all that relative. Lessen nutrient input, improve nutrient removal, and give the tank a good 48 hour black out. Generally 48 hours will not kill your plants, just the green water. This is pretty easy to recognize when you consider that plants are usually shipped in dark containers.


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## Sydneysider

Hi, may I also add that, green water can mean your tank is cycling again because of the huge ammonia spike you had since adding the snails. This often happens (New Tank Syndrom) and as advised daily water changes are needed. If you can get the brand over there I suggest purchasing Sera Nitrivec. I is a bacteria in a bottle and will sort your problems out very quickly. Seachem Stability will also do the same job. Just use either product as directed and you will have clean water, and save your fishes lives as well. ;-)


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## cal1112333

Hey you probably used rocaquarium's solution. However if you haven't I would suggest getting freshwater Asian clams. They do not have that parasitic breeding cycle, and can live in a wide range of temperatures, incapable of harming other animals and usually hide 90% buried in the gravel. And best of all it will only take a few (maybe 2-3 1" clams) to clear up you're water, infact you wont physically be able to produce greenwater faster than they will clear it up. And after a week you will need to add marine phytoplankton every other day or so or they will starve.

This is what I did, after 2 weeks of daily 30% water changes will constant cloudy water. And (obviously) I would recommend them to anyone who can get them.


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## CathyJ

How many/much water changes can be done before you destroy the bacteria that you need to keep the green and cloudy water out?


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## cal1112333

I would not do more than a 50% daily or a 80% every three days at most. A blackout for 48 hours worked for me but it came back a few months later and thats when I got clams. Had em for 6 months now still crystal clear water and none of the 6 clams died.


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## CathyJ

When you did the black out, did you just turn the lights off, or did you wrap the tank in black too? 

Where do you get these clams? I haven't seen them around here. I was going to try a pond clam, but they are out of season and buried in the ice and mud here now.

If the tank is to cold would it prohibit the good bacteria from producing properly? Our green tank had been running around 75 degrees. I have since added a heater. Also, are more substrates pron to green water than others?


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## Tyyrlym

No, the bacteria and algae that are in your tank are going to be more temperature independent than your fish. By the time you get it high or low enough to stop things your fish will likely be dead anyways.

Green water is fairly independent of substrate.


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## CathyJ

Thank you, I thought may be the tank was to cool for the benificial bacteria to out compete the bad.

I also was wondering if may be changing the substraight might help keep the green out. Thanks for clearing that up.


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## catfishtabbi

ah the dreadful single cell algea. all every ones telling you to do is what worked for me . HOWEVER take your water source into consideration if your municipality adds phosphorus you have to add phosguard to your filter media. basics dont feed your algea .rinse frozen foods with tank water they are loaded with sicilates-algea food. i had algea bloom so bad it killed 2 mothering swords all i did was use phosgaurd,rinsed my food and since i have a planted tank i use an acid buffer to adjust ihe ph neutral powders use a phosphorus buffer so steer clear if thats what your using.if you switch up to acid buffers and add phosgaurd remember phosgaurd sucks up the powder buffer that keeps your ph stable so be prepafed to do both at once.im sleepy i hope this isnt too much good night.


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## iamntbatman

Good point about the phosphorous. They sell phosphorous test kits, but at $10 or so I wouldn't spend the money. Instead, just find a LFS that will test it for you. One tap water test should be enough to tell you whether or not you've got tons of phosphates in your tap water.


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## CathyJ

Well, I took the black plastic off after a 4 day black out. 

The tank is still green. I haven't checked the phosphates yet, but will try to get that done tomorrow. 

I have ordered a live culture of Daphnia hopefully they will help before they become tank food?


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## Oldman47

Green water algae is not a problem for fish. It is even recommended as a first step for large scale breeders to first get the ponds green and then put the breeding fish in. The down side is the things people do to try to control green water. The blackout will kill off many of the individual algae but that means the dead algae become a rotting bioload. Always do a big water change to go with a blackout so that there will not be as much algae in the water when it starts. When the blackout is complete, another large water change is in order to remove the dead algae. There is no problem at all doing 50% water changes in any tank that is well maintained. The water just needs to be temperature matched and dechlorinated. 
As Cathy said, daphnia use green water as food so they will eat the green water. The daphnia will not be a complete solution because as they clear the water, the fish will see them and eat them. I keep my daphnia separate from the fish so that I can have them survive to reproduce and make more fish food. Meanwhile, I try to feed mine some green water once in a while because they do so well using it as food. I just can't seem to culture enough green water to feed them so I end up using other feeding methods.


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