This is a bit off topic but I planted aquaria people will better relate to
this one I hope.

Kept fish for years but this one has me stumped. 65 gallon with 10-15
additional gallons in a sump. Pump in the sump sends water through a
canister filter. Ammonia and Nitrites show 0 (new test kit too). Two large
Oranda's goldfish and or three rather large java and bolbitus ferns in the
tank. Bare bottom, no substrate.

This tank was set up for a year with a sand bottom and two Oranda's. We
moved three months ago and I took the sand out of the tank because Goldfish
are so messy it makes it easier to keep the tank clean, but kept everything
else the same. Same water system too. Now I have milky white water and have
had since it started to cycle. I recently lost one of my Oranda's and the
water cleared up a good bit. We added a second one back in and now the water
is cloudier than ever. Before this we had some cloudiness but never anything
like now.

I suspect that we have a large amount of free floating bacteria but I have
never seen a tank get this cloudy with just two fish and with all the
plants. Maybe with the sand bottom in it the bacteria had something to hold
on too? I have a new sand filter ordered to replace the canister. If that
doesn't work I am stumped. The tank is just ugly. All my others are crystal
clear (no GF in those)

Any ideas?

BTW we tried using Mardels Bright and Clear with no change. That seems to
indicate bacteria to me.
--
Kudzu *\\
The man that always tells the truth never has to remember what he said

A friend of mine had exactly the same problem. This went on for about 8 weeks. I put in down to a large amount of dissolved organics in his tap water which led to a massive bacterial bloom.

The only way we cured it was by me giving him some R/O water, which over a week or so replaced all of his tap water in the tank. This cleared it up after about a week.

He is now using his own tap water again with 25% weekly water changes.

Hope this helps

Stuart