Milky water - Please help.

[Cococalm]

Help !!!

I have cycled a 120lit /31 US Gal tank 2 months ago with 3 weekly water changes and added fish a month later. The tank is bare as this tank will serve as an Angel sorting tank with the view to breed. Currently there are about 20 various fish in it in holding for a friend while their tank cycles - 1 week to go.

The tank was crystal clear until a week ago when it suddenly became milky. Thinking I had a nitrate / nitrite spike, I proceeded to do a 75% water change with a 1/3 filter clean too. The water remained milky so yesterday I did another 50% water change with the remaining 2/3 filter clean out and adding carbon. No food is ever left in the tank after a feed .....

All new water was treated as usual when I do water changes. However, the tank remains milky. The tank smells like wet dust with a hint of fresh swamp which, compared with my other tanks - all planted, is completely normal. The water values, done daily, have all been normal - 26°C, NO3 >10 mg/L, NO2 >1, GH 8d, KH 6d, PH 7.2 and Cl 0. Lighting is 13 hours daily. What is going on ?

Any suggestions ? How do I get this tank back to crystal clear ? I know I can just ditch everything in a week and restart, but I still want to know what is causing this if my water values are normal so I will know how to deal with it, should it happen again, when I have my breeding fish in later.

Included a pic taken just before the posting of this message.

Thank you for your help.

 

[reefdiver]

Its usual for a new tank to cloud up. Im guessing you have a go filter?

 

[Cococalm]

The filter is an Aquaball by Eheim with 3 baskets and a sponge wafer insert. 2 baskets have medium sponge and one basket has loose filter wool. Aquarium was set up 2 months ago already and remained empty of fish until 3 weeks ago. Contains 7 Black widow Tetras, 2 Yo-yo adult, 2 corydoras and 6 Ancistrus - 1 adult and the rest juveniles between 4 and 6cm

 

[fort384]

If it is white in color, it is probably a bacteria bloom. It should clear up in a few days. It is common when starting a new tank.

I wouldn't clean the filter out anymore. You want the filter to have the opportunity to grow some beneficial bacteria. By cleaning it out so quickly after starting the tank, you probably have set the cycle back some.