基本上, 我的建議是
1. Mg keep 1400 is good. Only when Mg is high enough (1350 or above), KH and CA can hold without fluctuation.
2. Isolate the problem. Include test tank water outside of tank with same doser adding your CA solution. That can help exclude coral consumption and verify test kit expired or not.
3. From 2, you can find more truth. If tank water test before adding CA solution and after, show you same readings. Then you have either test kit issue or solution issue.
4. If step 2 show you expected result, than we exam what happen in your tank. I know you add CA and KH separately, which is good, but maybe something else.
5. If you Mg test kit is bad and cause your reading always at 1400ppm, but actually only 1000 ppm, then there you go, you won't be able to keep your Ca as I state in step 1.
6. BTW, please also check your saltwater source that keep expected Salinity, CA an MG from the beginning.
Sorry for English typing, I am very slow in typing Chinese.
Actually, just an announcement, from now on, folks ask me specific question in PM, I may dialog and explain in English. Chinese typing is way to slow for me. Please forgive me since I received way too many PM from PH8.4, FB, RC, and R2R.
