# Cloudy tank after water change



## Jill90 (Sep 4, 2011)

So today I just did two 50% water changes because my ammonia had been high. I Usually always do either 25% or 50% changes, but I wanted to do extra this time because I had waited longer than normal to do one. My tank is always crystal clear after I do water changes. I got back home a few minutes ago to find my tank dark and really cloudy. I did clean out the gravel really well, but not all of it. I did not touch the filters. My only thought is that there is a bacterial bloom, but I'm not sure why since I've changed the water so many times and this has never happened.
I'm also worried about my fish. It's upsetting to see cloudy dark water after working so hard for the little guys 
Oh by the way its a 36 gallon bowfront.
Any help would be appreciated, thank you!


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## Byron (Mar 7, 2009)

There are 3 usual causes for this. First, suspended matter in the tap water. Second, suspended matter within the tank that got activated (filter cleaning most often causes this, which I know you didn't do). Third, bacterial bloom because the water change was large and upset the biological balance. In this case as you've described it, if it isn't the first, it is likely the third.

A fairly full explanation of a bacterial bloom is contained in my article on bacteria, in the third post:
http://www.tropicalfishkeeping.com/freshwater-articles/bacteria-freshwater-aquarium-74891/

In a nutshell, by adding so much fresh water that was dechlorinated, it was a ready supply of nutrients for the bacteria and they simply exploded. As noted in that article, each one of these bacterium can reproduce in 15-60 minutes.

Byron.


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## Jill90 (Sep 4, 2011)

I do not think it is matter from the tap water, because within the first hour or two of changing the water it was clear and then about 6 hours later when I got home it was cloudy. So I'm guessing its a bacterial bloom.
Any suggestions on what should be done? It says to just leave it and it will fix itself and to get rid of the cause. But I do not think there was a cause besides that I messed up the balance by overcleaning. I hope at least...I would hate for anything bad to happen now!


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## Byron (Mar 7, 2009)

Jill90 said:


> I do not think it is matter from the tap water, because within the first hour or two of changing the water it was clear and then about 6 hours later when I got home it was cloudy. So I'm guessing its a bacterial bloom.
> Any suggestions on what should be done? It says to just leave it and it will fix itself and to get rid of the cause. But I do not think there was a cause besides that I messed up the balance by overcleaning. I hope at least...I would hate for anything bad to happen now!


I suspect you are correct. And it is not harmful, since you have plants. The bacterial bloom can cause an increase in ammonia of course, but the plants can easily handle this as it is not major. Oxygen gets consumed by the bacteria, but here again the plants help out. Assuming the cloudiness is not opaque so that you can't see through the tank, I would just leave it. Observe the fish to see if there are signs of heavy respiration, staying closer to the top than normal, gasping, etc. Increase aeration if these signs are present. Chances are they won't be.

I have a bacterial cloudiness that comes and goes in my 115g, ever since I replaced the substrate with sand. It took weeks, then suddenly became crystal clear overnight. That lasted for a couple weeks until I put some aragonite in the filter (to increase GH a tad, my old dolomite had given out), and its been slightly cloudy ever since. i also cleaned the filter then, probably had something to do with it.


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## Jill90 (Sep 4, 2011)

*Sigh* I actually do not have real plants in the tank just plastic. It's my first tank so I didn't want to start off with way too much at once. I eventually want to switch to a planted tank but not until I learn more about it and am ready.
Today the water did clear up though! I guess I won't clean so much at once from now on. My ammonia was still .25 though even after both of the water changes...it seems to never go down to 0. I don't want to do another change and mess up the balance even more though. Hmm..
Thanks for your help!!


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