Fresh water tank, brown water in tank and filter.

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PUMPKY90

Aquarium Advice Apprentice
Joined
Nov 25, 2025
Messages
26
Location
Pennsylvania
I recently cleaned my 29 gallon tank and I am running a purigen bag. This morning my tank was crystal clear after the water change after running for a bit, I come home tonight it's cloudy and all over my tank I see brown residue dust and inside the filter in looks like mud. I'm at a loss here.
 

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You may have overcleaned and now have a bacteria bloom. How well did you rinse the purigen?
Rinsed it very good like always. You are probably right it's the first big water change I've done to the tank. I never see a filter turn brown and build up "mud" this fast though
 
Rinsed it very good like always. You are probably right it's the first big water change I've done to the tank. I never see a filter turn brown and build up "mud" this fast though
It's possible that the purigen pulled out a lot of organics that were in suspension in the water which is why it's so brown. The water in the first 2 pics looks white which is a common color for bacterial blooms in new tanks or overcleaned filter pads but those don't usually create any brown dust. Organics on the other hand, will show up brown in pads like a polyfilter. Did you remove the purigen yet?
 
It's possible that the purigen pulled out a lot of organics that were in suspension in the water which is why it's so brown. The water in the first 2 pics looks white which is a common color for bacterial blooms in new tanks or overcleaned filter pads but those don't usually create any brown dust. Organics on the other hand, will show up brown in pads like a polyfilter. Did you remove the purigen yet?
no im still running the purigen. as of this morning the water turned crystal clear again. i do see a haze of brown reside on the glass and on tank decorations. is it safe to add my 6 tetras that i want to put in? i currently moved the fish to my other tank.
 
no im still running the purigen. as of this morning the water turned crystal clear again. i do see a haze of brown reside on the glass and on tank decorations. is it safe to add my 6 tetras that i want to put in? i currently moved the fish to my other tank.
Before adding the fish, do a full panel test ( pH, ammonia, nitrite, nitrate, general hardness, phosphate) of the water to make sure nothing is out of whack. As for the purigen, look and see that it hasn't turned brown. If it is, it's saturated with organics and needs to be recharged ( as per the directions). If it IS brown, it would make sense that the tank had a lot of organic waste in it which is why you are seeing brown everywhere. That would be a sign your filtering system in not adequate for your fish load. :unsure: If that isn't the case, I'd be on ammonia& nitirite watch after adding back your fish since that haze is typical of an overcleaned filter / new tank lacking nitrifying microbes. . (y)
 
Before adding the fish, do a full panel test ( pH, ammonia, nitrite, nitrate, general hardness, phosphate) of the water to make sure nothing is out of whack. As for the purigen, look and see that it hasn't turned brown. If it is, it's saturated with organics and needs to be recharged ( as per the directions). If it IS brown, it would make sense that the tank had a lot of organic waste in it which is why you are seeing brown everywhere. That would be a sign your filtering system in not adequate for your fish load. :unsure: If that isn't the case, I'd be on ammonia& nitirite watch after adding back your fish since that haze is typical of an overcleaned filter / new tank lacking nitrifying microbes. . (y)
Thank you, I'll check tonight everything
 
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