Stop dosing the reef roids. Coral don't need them and they just raise phosphates.I use RODI water from my LFS and I’m going to see tomorrow where I’m getting a salifert phosphate test. Because I been good the only thing i can think is me feeding my coral with reefroids
FWIW, the Hanna ULR checker will misread if there are particles in the water, the sample must be clear water.