I have a pool that I can't seem to get opened this year. It's being very stubborn about wanting to keep a deep pea-green patina, and the trips to the pool store are starting to become expensive. I found this site yesterday, and now I'm feeling a little more hopeful. I ordered the TF-100 XL test kit last night, so hopefully I'll have some goods numbers in a few days. Until then I'm looking forward to exploring the Pool School and learning everything that I can about pool maintenance.