So I got a reading of 0 but i have turf and algae growing i see they have a 0.05 accurate difference so should I just take that my p04 is higher and side note my sod are losing color. And I'm not running gfo
More than likely the algae is consuming all the phosphates in the tank giving you a false reading. If you have an algae problem with no testable phosphates that's my guess...