I have had a diatom problem for a while now and its not getting any better. My Nitrates are 0 and with GFO my po4 is under 0.03 ppm. I'm starting to think its my RODI water. Because if I go a month with out a water change it slows down. But as soon as I do my water change its like pouring gas on a fire. What I dont understand is the water coming out is reading 0 tds with a inline tds meter and a hand held meter. My water company dose you well water so I guess that could be a problem. Other than the diatoms algae is no problem knock on wood.