I've developed cloudy water In a 90 gal tank that has been up for about 6 weeks. Moderate to heavy planted with Amano AS. After 4-5 weeks when ammonia and nitrite zeroed out, I pulled up a few stemmed plants to trim and replant. Water turned slightly cloudy with the disruption of substrate. So I added about a half cup of diatom powder to a magnum 350 with micron cartridge to polish. Water cleared up in 24 hrs. I ran the filter this way for three days. As soon as I stopped using the diatom powder, the cloudiness returns in 24 hrs. Running the filter with just the micron cartridge doesn't help. White hazyiness like new tank syndrome. I can keep it clear by using the powder 24/7, but I can't figure out what's causing it so I can fix it. Any ideas?
Ammonia and nitrite = o
nitrate = 5 ppm
PO4 = .03
ph = 6.75
kh = 3.0