Mike,

Welcome to the forum. From what you say your chlorine could be quite high, and if you have a liner pool, it might start to get bleached.

Without a good water analysis, we can only suggest that you are chlorinating at a rate higher than necessary. The fact you don't smell any chlorine tells me that. I would maintain your 15% setting until you post that water analysis and then we can give you better advice.

Hope this helps.

Pat