Leaching phosphates from rock

[syncro]

Originally Posted by asylumdown

I think I have figured out why biopellets are so closely linked to cyanobacteria, and why cyanobacteria seems to thrive in low nutrient tanks if anyone ever cares to know (surprise, the solution is NOT to further reduce nutrients in the water).

I'm interested!

I have wondered if phosphates were leaching from my sand or rock. To test, I left sand, rock and nothing (control) in small containers with DI water for a week. Measured 0 phosphates with a seachem test kit. But still have cyano. Dosing nitrates seems to help green algae outcompete cyano where nitrates are always 0 (it also helps bacterial blooms!).