Reef Angel Forum

Here's my situation... I have calibrated my salinity probe with 35 ppt refractive index standard solution and when in the solution the probe is reading 35.0. When I move the probe to my RODI water it reads 6.0 and I know that is really at 0. When I move the probe to my sump the probe then reads anywhere from 34-35.6. I know that my water is really at a 1.025-1.026.

Without just saying take 10 points off the probes value is there a way to force the adjustment?

6 is the lowest the probe reads. It's normal. It sounds like you're probe is reading perfectly for 1.025-1.026.

So how do you know what your salinity really is then? Do you just mentally subtract 10 points?

Do you keep your tank at 25ppt?
Salinity measurements are in ppt and not specific gravity.

35ppt is 1.026