In my 20+ years of aquarium hobby I have never experienced this. Then again, this is my first dirt tank. 🤷♂️
Setup: 40gal tank with dirt and sand (play sand). 2 inches of organic soil capped off with 1.5" of sand.
Filtration: I'm using two internal filters. A Fluval U3 and a Sicce Shark 600. I'm also running an air pump through a Hygger air stone.
Light: Hygger 48" LED
Plants: Anubias, java ferns, a huge Amazon sword, hornwort, cryptocoryne parva, ludwigia pepens and couple other unknowns. For nutrients I use Seachem root tabs, Co-op easy green, flourish trace, flourish iron. I dose once a week with easy green and flourish trace, and every other week with iron.
Inhabitants: A single GBR, 9 lemon tetras, 3 celebes rainbows, 3 praecox rainbows, a bunch of cherry shrimp and ramhorns snails.
This tank has been running since December. Water tests as follows: 0 ammonia, 0 nitrites, 15ppm nitrates, 7.5 pH. Temp. is currently at 82 degrees.
The cloudiness was there pretty much from the beginning. I remember when I first filled the tank and the sand settled, the water was clear for about a week. After that, I would see haziness/cloudiness to various degrees throughout the day. I do 40% water changes every 2 weeks since the plants are keeping the nitrates at bay. Whenever I do a water change, the water in the tank will clear up to near crystal clear, but a few days later it will become hazy/cloudy again. I don't think this is a bacterial bloom. I'm seeing very fine microparticles in the water column. I recently changed the media in the Sicce 600 filter to try and combat this cloudiness. I used two very fine sponges and topped it off with a polishing pad. This made no difference.
Is it as simple as my filtration not being good enough? Both of the internal filters are rated for tanks up to 40gal, so two of them should be enough, no? I have a Fluval U2 in my 20gal and the water is crystal clear! The only difference in these two tanks is the substrate.
Is there a different filter media I can try to trap the microparticles in the water column?
Thanks all!