I have been reading all the great posts here and I know SOMEone will be able to help me!! My 3 1/2 year old pool is having 'issues' and I am worried it may have something to do with the calcium hardness. I have never tested it before this year because until now I only had the chlorine/pH test kit.

This Spring I have a really bad white 'ring around the pool' and the plaster looks stained pretty much throughout the pool - it looks splotchy and brownish. It does not sweep off. Is this what you refer to as 'scaling'?

Here are my test results:
CH - anywhere between 460-500 (tested my tap water too, it's only 20)
FC - 2
TC - 2
pH - 7.4 (just added acid because pH had gotten up to 8.2 - my pH always seems to creep up, so I have to regularly add acid)
TA - 110
CYA - 45 (just added some this week because it was almost non existent)

I have a salt water generator and unfortunately was not good about testing the pool this winter (I am in CA). I had black algae in a few spots last month (Chlorine generator stopped generating and I didn't realize it... it was low on salt, but that is taken care of now).

So I guess my questions are...
Is my calcium harndness too high? (I've seen conflicting information)
Where does the calcium come from??
Is there anything I can do about the ring around the pool and the 'stained' plaster?

Thanks so much for your help!
Nicole