I agree with Russel, except I run my tank @ 1.026 instead of 1.025.
Either way, your current Sg is too low for the long-term health of many corals, even the most easy to keep ones.
Running your tank @ 1.023 is pushing the limits of near death for many inverts too ... hermits, snails, shrimps, all the life on your rocks such as copepods, isopods and amphipods and such, mysids, sponges, the list goes on ...
I know, seems like it's not much of a difference, but ya, that's all it takes.
Slowly bump your Sg up to what we recommend and see how things go after a month or so.
And when I say slowly, I mean no more than 1 point per day. Otherwise you'll upset or kill what you have left.
So, today is 1.023. Add enough salt to make tonight 1.0235
Tomorrow night make it 1.024 and so on.
Slow and easy is your best approach to the hobby
I know my recommendations above seem extreme 'cause fish can handle faster swings, but your corals will be happier if you take it slow as I suggested