Thanks to everyone for your replies.

A couple of things. Great idea on getting the water tested. I don't want to rely on a "strip" test to assess the amount of CYA in the water. I have ordered one of Ben's Test Kits and am anxiously awaiting its shipment/arrival.

I've only been at this for a month, the pool has been filled for just over a month, but would my calcium build up already be a problem? As I mentioned, I was only having to run the SWG at 35 - 40% to maintain my chlorine. It is only in the past couple of days that I have noticed the drop in chlorine and increase in PH. I assumed, maybe incorrectly, that the accidental overflow and resulting refill caused these issues.

Finally, I learned from this site that I can use bleach to suppliment my chlorine when necessary. Great advice and I will use it to help raise my numbers if it turns out to be necessary. I have a Leslies near my home and will have them test my water for CYA. I will also add acid to lower my PH and will continue from there.

Thanks Again, I truly appreciate the advice!

Mike