False High PO4 Test???? Any thoughts?

N4sty T4te · Jul 1, 2017

So just ran my weekly Po4 Test. It came back 0.21 on a low range hanna checker.

I'm thinking its an innaccurate test. I typically check Po4 mid-day before feeding. Before water changes, etc.

This test was done after a water change with sand bed siphon, and after feeding reefroids, reef chili and frozen foods (2.5 Hours ago)

I'm going to retest tomorrow and see how the numbers look. Any thoughts? I've never had a reading other than 0.00 ... I've been working on raising the nutrients actually.

N4sty T4te · Jul 1, 2017

Ok well guess I just answered my own question, decided to pull from my return chamber in the sump for test water and got a 0.08 reading.

Must still have some food floating around in the DT.

Going to pull another test tomorrow morning and see where it's at. My guess is that it will be at or near the typical 0.00 in the AM.

BlueCursor · Jul 2, 2017

If you pull water from your sump make sure you get it from an area that doesn't have any film on the surface. Try to get the sample from as clean an area as possible so you are testing only what is in your water.

Randy Holmes-Farley · Jul 2, 2017

The organic matter in food or water surface scum shouldn't appreciably contribute to a phosphate reading because organic phosphate typically won't hydrolyze during such a test (special methods are needed for that). Particulates may lead to light scattering that could give a false high reading.