We had a fiberglass pool for years until the gel coat started to wear off. We had the pool renovated this past year and the list of instructions for maintaining the pool includes a recommended 170-180 TA. I have NEVER heard of such a thing but this is the same company that coated my previous pool -Shastaglass. I've called them twice (and have it in writing). Can you think of why they recommend such a high TA level. I presume it's a proprietary coating and, as such, am following the installer's instructions but it's driving me crazy. Any one else ever encountered this?