Clouding Tank

[kreacher]

Hi guys

I have a 180L brackish tank at 1.05sg with 3 monos, 1 scat, 1 goby and 1 archer fish.

It has 2 filters at each end and is 15-20% water changed each week. I only ever clean each filter in water from the tank and always clean one leaving about 2-3 week gaps before ill clean the other. Each water change I gravel clean.

The tank only has rocks which have been used in other tanks with no issues. The issue is that tank keeps clouding, it looks like a bacteria bloom but as i understand they clear after 48 hours or so and this just gets worse the long i leave the tank without water changing it.

I have tested the water for everything ammonia, nitrite nitrate and PH all are fine and at safe levels the only thing i can think could be causing this is the lack of a skimmer. I have read loads on brackish tanks and most sites and people say you don't need one but I just wondered would this help stop it?

 

[nmonks]

Cloudiness in tanks comes down to three basic causes. So it's a case of checking them off one at a time.

First there's silt. Mostly this comes in from things like gravel and sand. (It's almost impossible to deep clean silver sand so well it doesn't bring in at least some silt, so far as I can tell!) Mechanical filtration is your friend here. Given the size of your tank and the livestock, a turnover rate of 6-10 times the volume of the tank would not be out of line. Filter wool is the best thing for mechanical filtration when you have serious silt issues. Replace (or at least wash frequently) the wool until the silt is gone. Stirring the sediment during water changes helps siphon off the silt as well.

Bacterial blooms can occur, but are typical of unstable, poorly filtered tanks. Again, ample filtration is the key, but this time biological filtration is what you need. As I have said many times here at TFF, in most tanks the important thing is to balance mechanical and biological filtration; chemical filtration (carbon, ammonia remover, etc.) are largely a waste of filter capacity.

Algal blooms (diatoms, usually) are characteristic of new aquaria. Specifically, diatoms thrive in conditions where the lighting is poor (so green algae can't get established) and the water quality is variable. UV sterilisers can help dramatically, but otherwise most tanks settle down within months. Mechanical filtration will also help.

Cheers, Neale