Hi, thanks for the replies. Here is some more info on my setup :
64 liter / 17 gallon cube tank
Eheim 2211 canister filter
2 x 11W lighting, for some low-light plants (anubias, java fern), sort of medium to heavily planted (all tied to roots / rocks)
I have two chunks of natural driftwood (all properly cleaned, scrubbed, and soaked in scalding hot water), a castle, and some rocks
A pair of apistogramma baenschi
Substrate is this :
JBL Aqua Basis Plus | Aquarium Supplies
+ Black quartz sand on top
Fertilzers : EasyCarbo + JBL Ferropol + JBL Ferropol 24
I just (last night) added a UV sterilzer, thinking maybe this would help
Tap water is spring water which we produce on the property
Fishless cycle totally completed beginning October, fish added thereafter.
Previously I was heavily planted with roots plants (hence the Aqua Basis substrate). This failed miserably, ending in a horrible festival of what I think was brown hair algae and diatoms. Ripped out the plants, re-planted with more suitable plants, light-wise (some of my plants were medium light, which was at least part of the problem, I believe). Removed the bio CO2 system at the same time, as this was creating some leakage / mold problems.
Before I did the plant renovation, my *only* problem were the diatoms and the brown hair algae. When I removed the plants, I did a massive brushing off of diatoms from the decorations, and rinsed (in tank water) the plants that I was keeping to get diatoms off.
It seems to be no coincidence that my bacterial bloom problems started then. I must have upset the equilibrium or something when I moved things around. The cloudiness is milky white, and not green, which says bacterial bloom to me.
Otherwise, I am extremely faithful about tank maintenance. I do at least 2 PWC's per week. I have an Eheim battery operated gravel vac. My fish are so used to seeing it that it has now become a game for my male apisto.
I STILL have a very noticeable diatom problem, along with the bacterial bloom. My fish, throughout all this, are totally fine and have even (I believe) attempted to make babies amidst the brown and white crap.
Any comments / advice will be appreciated! One thing I am wondering about is my substrate : now that I don't have rooted plants, is the Aqua Basis a problem (the nutrients in the medium are going nowhere as the plants are no longer rooted but all tied to rocks / driftwood).
Anything else you can think of to help me?