Well, I've been lurking around this site for about a week and am really learning a lot. Here's a short version of why I landed here....
My pool is about 3-1/2 years old and I've had a pool service taking care of my chemicals pretty much the whole time up until a couple weeks ago. The last several months I noticed a lot of turnover (seemed like a different service person every few weeks). Also, they had started coming in and putting in chemicals and then leaving without even turning on the pump. The last straw was a couple weeks ago when I saw the guy dump two full bottles of chlorine in the shallow end of the pool, pouring from about 3 feet above the water surface and splashing it around. Then again, left without turning on the pump. Needless to say, I've now canceled my service and will try to handle the chems myself, with the help of this great website/forum.
I brought a sample of my water to the pool store and found that the CH and CYA were through the roof. CH = 960ppm and CYA = 200 ppm. The pool service said only way to bring the levels down is to drain the pool, which they agreed to take care of. They sent a guy over who tested using a Taylor kit and verified the results. So the pool was drained and refilled and startup chems added. Now I'm on my own and am looking forward to handling this myself and saving some money in the process. I've got a TFT-100 test kit on order and should receive it next week.
Here's my theory on how the levels got so high. I have a Nature2 Fusion system. This system has a chlorine tab feeder that works in conjunction with a mineral cartridge. The pool service never used the tabs (only liquid) and so the Nature2 only had the mineral cartridge in it. I even changed the cartridge one time (about a year ago). My guess is the cartridge ended up causing the levels to go up. Do you think that's possible?
Anyway, now I'm going to try and figure a way to remove the cartridge. With no trichlor tabs or mineral cartridge, the water should just flow through it with no effect.
Thanks for a great, informative site.