# bacterial bloom in established tank



## silvershark

hi everyone, I had an established tank that has been doing great for years now , unfortunately I was away working from home for a month and my wife decided to clean the filter , she said she cleaned both the sponges in tap water NOT THE TANK WATER this was on the 10th of January since then I seem to have a bacterial bloom, its been over 5 weeks now should I just leave it will it fix itself once new bacteria grows in my filter ? she also cleaned all the rocks with a wire brush . I haven't lost any fish although 4 corrydoras and 2 platys have had finrot witch I have cured the other ones are fine, what I want to know is will I get a sudden spike of nitrite like new tank syndrome ? I have put my filter on full power to give the fish plenty oxygen should I keep it on full power the water clears a good bit if the filter is on a low setting ? also I have been doing a 40ltr water change every week should I cut this amount down? just like a new tank it gets worse after the water change here is a list of my fish and water quality. what should I do.
200ltr fluval tank
u4 fluval underwater filter.
live plants, --amazon swords
rocks.
Dorset pea gravel.
heater, 77f
ph. 6.2 roughly
ammonia 0.25
nitrite 0ppm
nitrate 0ppm
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4 platys
8 corrydoras
2 black mollies
8 scissortails
2 paired angelfish. thank you. any advice welcome


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## beaslbob

silvershark said:


> hi everyone, I had an established tank that has been doing great for years now , unfortunately I was away working from home for a month and my wife decided to clean the filter , she said she cleaned both the sponges in tap water NOT THE TANK WATER this was on the 10th of January since then I seem to have a bacterial bloom, its been over 5 weeks now should I just leave it will it fix itself once new bacteria grows in my filter ? she also cleaned all the rocks with a wire brush . I haven't lost any fish although 4 corrydoras and 2 platys have had finrot witch I have cured the other ones are fine, what I want to know is will I get a sudden spike of nitrite like new tank syndrome ? I have put my filter on full power to give the fish plenty oxygen should I keep it on full power the water clears a good bit if the filter is on a low setting ? also I have been doing a 40ltr water change every week should I cut this amount down? just like a new tank it gets worse after the water change here is a list of my fish and water quality. what should I do.
> 200ltr fluval tank
> u4 fluval underwater filter.
> live plants, --amazon swords
> rocks.
> Dorset pea gravel.
> heater, 77f
> ph. 6.2 roughly
> ammonia 0.25
> nitrite 0ppm
> nitrate 0ppm
> ------------
> 4 platys
> 8 corrydoras
> 2 black mollies
> 8 scissortails
> 2 paired angelfish. thank you. any advice welcome


Hopefully it is temporary.
I would add some fast growing plants like anacharis to consume ammonia directly and remove co2 which results in low pH. the swords got behind the ammonia and co2.
you could also speed things along by killing the lights and reducing feeding to once per week. 

these things happen. Just takes some time to rebalance out the aquarium.

my .02


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## Bilbo Baggins

I have heard that on situations like this where fast removal of ammonia and nitrates is neccesary then Duckweed is the aquarists friend, it consumes ammonia at a fast rate, of course it is not to everyones tast and multipys rapidly. your 20% water changes is the right thing to do, so hopefully the filter will soon be back up to scratch and all is well again. Dont know whether I would me mad with my wife if she did that, on one hand its good that shes taking an interest in your hobby, but on the other hand she needs to do it right. Good luck and I hope things soon get back to normal.


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## jeaninel

So your wife removed the gravel and cleaned it as well as the filter sponges in tap water? If it's been over a month and your still seeing ammonia sounds like you lost your cycle and are starting over. Keep testing the water and doing water changes as needed to keep ammonia and nitrites at bay. Fast growing plants like anacharis and water sprite will help.


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