Well to solve my salinity issues I brought a brand new Pinpoint Salinity Probe. It came with calibration solution. Not knowing this I bought additional calibration solution. So I ended up with two different bottles of solution.
Not thinking about it, I used one bottle, calibrated, then corrected my salinity. It wasn't terribly off. Fast forward a few months, well things still don't look that great.
So I figure I'd re-calibrate using the same solution, same result as before. Then I figure I'll try the other bottle. The result was totally different.
Basically, two bottles of brand-new from PA calibration solution, stating they have identical salinity levels, ended up having totally different readings. We're talking 1.029 vs 1.0265.
I know which one is correct because I received orders from WWC and Cherry Corals and tested their water. They said they run between 1.025-1.026. Their readings matched very close to the "good" calibration solution.
I DO NOT recommend using PINPOINT brand calibration solution. The good stuff was made by Sybon.
