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I recently set up a 60 x 30 x 30cm Aquael tropical freshwater aquarium which came with an Aquael 300 internal filter.
The water has been milky since the start! I believed this to be a bacteria bloom and assumed it would be resolved within a few weeks but it has now been over a month!
I’ve got carbon in the filter and I’ve just added some Pure bacteria balls to the filter because I was told I may be lacking in beneficial bacteria. I do regular 10–20% water changes, once a week to be precise.
Regarding fish, I started with a three tetras and a Bristlenose and after two weeks I added a Betta and two Endler guppies. I also have four Amano shrimp but I haven’t seen them since I put them in.
Please can you advise? WESLEY OAKLEY, EMAIL.
AIt sounds as though you didn’t cycle the tank before you added the first fish, so as you surmise, the bloom is probably caused by bacteria in the water column living off the fish waste that the filter is as yet incapable of fully dealing with. You don’t mention the results of any water tests you’ve carried out but I suspect they will show elevated levels or ammonia and nitrite as well as the expected nitrate reading. Four weeks into a ‘fish-in cycle’ then things should at least be improving bacterially and the filter slowly catching up with the bioload of the stock in the tank. The regular water changes will have helped prevent the death of the fish but they may have suffered some long term damage from prolonged exposure to ammonia and nitrite, so keep a close eye on them for signs of disease and parasites. The addition of the bacterial supplement should be helping speed the whole process a little as well.
Bacterial blooms are common-place in new tanks and usually come and go during the fishless cycling process we recommend, so while unsightly, they are usually harmless. Yours is probably taking a little longer to clear as you are having to carry out regular water changes to keep the fish alive which dilutes the waste the bacteria in your filter feeds on. In a fishless cycle, you can simply let things take their course but you don’t have that luxury as the fish would suffer should you stop the water changes.
As long as there is no green tint to the bloom (which would show an algal constituent), carry on with the water changes and maybe reduce the feeding slightly. Given time the bloom should clear by itself.
Regarding the missing shrimp, crustaceans can be extra sensitive to poor water conditions so may have fallen victim to the water quality if you haven’t seen them for a while. Don’t give up on them just yet though, they may just be hiding away somewhere. BOB MEHEN
Cloudy water in new tanks is often caused by harmless bacterial blooms.