If you alredy had a large amount of corals I would say maybe you need supplement but since you are just starting with them I would say that weekly PWC
would be enough. The fact that you have good corraline algea tells you that calcium is OK for now. I have a whole tank full of corals and I still just do weekly PWC
and calcium stays between 375-425. If for some reason I have to go a couple weeks before PWC
I use Tropic Marin Bio calcium. but most of the time I just do PWC
. Get a Calcium test done before you add any. More than likely you wont need any.