I am sure this has been covered many many times. I beg your indulgence.

My 55 gallon has 340 calcium and 9 alkalinity.Ph is steady at 8.2.

I only keep a few shrooms, zoos and rics. I have been thinking of adding some easy LPS. No plans for SPS, clams, etc.

Now, my question is....are these levels okay? I know the calcium is low but does it matter in a tank with these types of corals? If I need to raise calcium, what is the easiest and safest way to do that?

I use IO salt and I change 10 gallons weekly. I do not add any supplements.

TIA