pebblensalt

I moved into a home that has a 13,500 gal pool, pebbletec surface, saltwater, sand filter, about 8 years old. The previous owner had been using a floating chlorinator in addition to the SWG, using 1/2 to 1 3" tab per week, which I've continued. His reasoning on doing that was to "save" the expensive salt water cells. I did increase the chlorine output setting from the salt system and have used less of the tablet, and the chlorine levels have looked ok on the test strips, which I believe are a bit imprecise. I don't know when he last drained the pool. I took a water sample to a pool supply store about 2 weeks after we moved in, was told everything was fine. we've been here about 7 weeks now, and we had a heavy rain here in Arizona (highest in the past 1000 yrs?), and I had to drain water from the pool (I did the 2nd backwash since we came here). The pool also has an auto-fill if the level drops. I took a water sample in to the same store, and was told my CYA and salt levels were too high. I asked how the salt level could be higher when the water was diluted with rainwater and just got a shrug. The next day I took water samples from my pool at the same time to 3 other stores (one the same company 2 others were Leslie's) and got 3 different results. So in total, 4 stores and they all had different results and advice on what to do. They all recommended complete drain of the pool "at the end of the season" to reduce they CYA. One recommended cleaning the salt cell as a first step. I purchased chemicals, but haven't used anything. The CYA level in all tests shows its over 150ppm, my test strips also show it in the high range. -My pool looks clear, but my daughter likes to open her eyes underwater and says the water stings a lot now- it didn't when we first moved in. -I started using mesh bags in the pool cleaner and skimmer baskets due to small leaves that go through the holes in the baskets. I found pieces of what looks like the pebbletec in the cleaner basket (looks like pieces of glass/plastic a little larger than sand) and am concerned about damage to the pool surface because of the chemical balance. I am purchasing the Taylor K-2006 test kit from Amazon, will post results after I get it. Questions: -do I need to drain my pool now to prevent damage to my pool surface? -do I need to use phosphate reducer if I don't see any algae? -should I ever need to use added chlorine with a salt pool? (it has a "super chlorinate" function on the control panel) advice is appreciated.