i am using ato
i am not sure the material is reef safe
i calibrated once and when i just checked it had drifted to 1.028
which means my salinity is actually 1.024 now WC's having been made with weak SW
checking with salifert. testing DT and SW drum. last test 10 and 8.6 respectively test could be bad exp. date 1/2025
i am not dosing anything regularly i have added Mg and ESV B-Ionic two part a couple of times
i have included pictures of a couple of rocks 1744 the darker one is still in my DT it shows holes through the top left that were not there in April 1747 is a rock that i removed it shows white areas that have receded rather than encrusted or algae'd over. this rock is in a quarantine set up after i removed it from the DT
I know refractometers are rugged and can take a beating. However, the calibration of the refractometer is extremely delicate. Any bump, shake, etc will knock it out of calibration. At least that’s the case with mine. Therefore I check calibration every time. I also use an Apex, so I do not have to use the refractometer unless something isn’t reading right. So we know there was some salinity inconsistencies. That will effect your alk readings. I also do not know how often you test alk, but I test it every day at the same time and record it in a spread sheet. I also mix new SW to 1.026, measured with the refractometer and then I test the alk of the new saltwater. This eliminates any possibility of an alk swing to my system.
If I were you, I would get my salinity to 1.025 or 1.026 and then make sure it’s staying there with your calibrated refractometer, daily. And then test alk and record it, every day, at the same time to see what it’s doing. Don’t make any other changes to the system until we get some consistent knowledge of what your alk is doing after getting salinity stable.
Seeing “new” holes show up in a rock is HIGHLY suspicious and suspect. But I wouldn’t do anything at this moment until we see what the alk numbers do.
The other issue is the potential of calcium carbonate rock to dissolve under low pH OR low magnesium. It’s highly possible and could explain new holes in live rock. Do you have a pH meter? I also noticed your Mg test was in the 900’s previously. If your salinity was off then that Mg number could be suspect as well.