Thanks for the response. I checked the phosphate in my tank and they were extremely high and decided to check the RO water itself and came back with that reading of .06. I’m using a Hanna checker. I’ve heard they’re inaccurate for testing fresh water. Do you know if that’s accurate?No it should be 0.
Well I would certainly suspect the Hanna. Can't hurt to try the Red Sea kit even if it's out of date. But I think one way or another you need to confirm the phosphate. I wouldn't try testing the RODI with any test kit designed for saltwater testing. Mix up a small batch of saltwater with your salt to the concentration you normally run and let it sit for a couple hours then test it.Was searching threads and came across this one. I’m having similar problem with my Hanna checker. Phosphates in my tank have been reading high in the last couple weeks. I thought it was from dosing Red Sea AB+. Stopped dosing and checked about 5 days later and phosphate went up. Was reading about .30, now is reading about .40. Started thinking what other causes there could be. Checked my rodi with the Hanna checker and it read .18. Here’s the kicker. TDS coming out of rodi reads 0. I have another handheld tds checker and it also reads 0. Is it possible to have 0 tds and have phosphate readings or do I have a bad Hanna checker? I have a Red Sea phosphate test kit I could check against, just haven’t done it yet. It’s out of date though.