So, I ordered a Hanna phosphate checker to get a second test for phosphates. My red sea comes up undetectable, but the Hanna showed .16. Is this enough phosphates to have cyano grow on the sand bed? And because of these phosphates would vodka or vinegar dosing be beneficial? I'm not sure where the phosphates are coming from. Inline TDS meter is reading 0. I do 5-10 gallon water changes weekly in my 65g
Did you buy the high or low range Hanna checker? If it's the low range, you have to multiply the test result by 3.066 then divide by 1000 to calculate po4
depending on what you are keeping, I would say .16 is on the high side. Most shoot for a .02-.03 po4 range
I would retest your Rodi with a handheld TDS meter just to make sure. Also, have you tested a freshly mixed batch of your saltwater when doing a water change?