Thanks for the info. You've got yourself a miracle pool! If it were fairly new or newly replastered, then the curing of the plaster would have a rise in pH, but... OK I'll stop trying to figure out why you aren't seeing as much of a drop in ph when using Tri-Chlor tabs nor having your CYA go through the roof like it did in my pool. Must be that Florida sun and rains (I lived in Boca Raton for a year, so I'm jealous that you've still got swimmable weather).