Salinity is 1.025
Hmm, I’d say if there was one worry I have is with alk, it seems to drop about 1dkh between water changes
Not always the case. Some corals are more tolerant than others. I would say torches and zoas are pretty picky. ESP when it comes to alk. How are you testing and maintaining your alk? 7 is on the low side, though corals can adapt to a lower alk, an alk that’s 7 that isn’t maintained can shift points in the couple weeks you aren’t dosing or doing WC.
Testing is either Red Sea or salifert, the Red Sea one seems hard to read as the colours are so light. I’m not maintaining to be honest, just letting the WC take care of it. I do have some Red Sea alk solution so I’ll do another test tomorrow and dose whatever has dropped. Should I try and raise the alk past 7?
What salt are you using? And what is your WC schedule? Size of tank and water volume? Coral stock has a lot to do with it. People with more calcifying corals use up lots more alk then someone with a few sps frags. Water volume is also another. I have seen people get away with WC to maintain alk, but these people do it religiously every week! I think it’s easier to test then maintain with a 1 or 2 part dosing system. An alk of 8-9 would be more ideal. So if it shifts a point, you won’t get down to 5-6 like you were at before.
Make sure to take your bag of salt out and mix it around. Sometimes during shipping salt can settle. Also happens more frequently with cheaper salts. I’ve never had this happen using tropic marin pro, all the levels are even top to bottom and I never had to mix it like my instant ocean salt mix
