- Roger that. For future reference -- since many on the forums use the Hanna Phosphate ULR -- the conversion to ppb phosphates (PO4) is in your current measure: 11 X 3.0661 / 1000 = .034 PO4 in ppb
- Again, IMO, that is a perfect number for phosphates (PO4). I would hope to see NO3 (nitrates) around 3-5 to have OK nutrient balance IMO. Cannot be your problem unless that has been extremely noisy or imbalanced.
- You have APEX (I am a big fan), so nothing noisy with Temp, Salinity, ORP right?