Refractometer calibration solutions

[Eric79]

I've had a refractometer for a few years and I used to be really good about calibrating it at every water change. Recently I've been slacking and I probably did 5 or 6 water changes without checking the calibration which was a stupid mistake on my part but I got lazy. My corals started looking a little funny and when making this week's batch I decided to grab the 2 bottles of calibration fluid I have and check it out. My problem is that the 2 solutions are reading differently. If I calibrate using the pinpoint solutions to 1.026 I get 0 when I put RO water on the refractometer and 1.025 when I check my tank water which should mean I'm right on the money but when I use my sybon calibration solution it's way off and reads around 1.031 but doesn't 0 out with RO water using that solution. What do you guys think ? Is my pinpoint solution right or the sybon solution? ???????

 

[BKLYNREEF123]

If I were you I would buy a new bottle of solution and calibrate to that, and forget about zeroing out to RODI. From what I have read you cant use RODI as a calibration fluid to zero anyway so I wouldn't use that as a reference point. If your corals are not looking right why not spend a few bucks and make sure your salinity is on point with fresh calibration fluid? just my .02 im sure plenty of people will tell you to zero it out with RODI.