Sps dying from tips .

[Suohhen]

@Rmckoy Can you look at what I posted. The top three reviews on Amazon complain about inaccuracy and the person who answered the question about the .003ppt inaccuracy claimed to have called Hanna and was told that is just the way it is, "it will never match the refractomer". I don't doubt that your refractometer is poorly calibrated but that doesn't mean the Hanna is any less correct.

 

[IslandLifeReef]

Hanna alk is the green liquid ....
I double check with salifert often .

Hanna phosphorus ulr Uses the white powder . I can see where that can give different test results .

The 1.030
Was the calibration Of the old refractometer but the Hanna was calibrated .
the water was correct

The Hanna was calibrated , the refractometer is a older cheap Amazon one .
Has never been reliable it wasn’t calibrated

Well, you seem adamant that your tank is stable and that your testing is accurate, so I really don't know what to tell you. A stable tank with a PO4 of 0.1ppm shouldn't cause a sudden problem with your acros. I wish you good luck in figuring it out.

 

[coralfishreef]

Maybe triple check your salinity with an old school, floating, glass hydrometer.

I check salinity at least twice a week. Once a week or so I will calibrate the refractometer using the hydrometer.

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