Mac, I will read more on the SWG, my concern is that I have travertine coping and decking (a lot of it in my small yard). I was told that it will start eating away at the travertine, and I do not have it sealed. I may need to stick with the chlorine. I was going to the pool store every few days to get a reading on the water, on 3/11 my CH was 600 and they did not mention that it was an issue, on 3/23 ch 275 and on 3/26 my CH was 350. I don't think this Pool store knows what they are talking about, the turn over on people is a lot, and everyone is always training.
Hey Vegas - I remodeled my pool 3 years ago with travertine coping and I have zero etching of the deck. It looks just as beautiful as when it was installed. Here's an old thread of my build. I got so busy at work that I never did upload the total finish but I'll do it in the next week. Mine was not sealed but if I start to see any degradation, I will go to Home Depot and get a sealer.
West Houston Pool Renovation
The convenience of a SWG can't be overstated. Not having to go to Walmart, especially the horrible customer service Walmart close to me is worth it alone. My pool is pretty large and it takes me buying 10 - 12 gallons to shock at about $3 a gallon. I get a lot of hard looks carrying that much bleach in a cart. Plus I travel a lot so it's hard to sometimes to maintain proper FC levels. I looked into getting a auto liquid pump but I'd still have to buy the bleach bottles. I looked into having drums of bleach delivered to my house but it was very expensive. The SWG pays for itself for me quickly. Stick with the bleach at first but if you're like me, eventually a SWG is just too convenient and economical. I helped a friend with a new build find a cheap SWG on Craigslist. It took us about 2 hours to install and setup. She is a happy camper. You might be able to find a real cheap used control panel then you can buy a new cell.
Something is not adding up with your CH. Even if your fill water is 350, that should not ever increase your CH above that number. It doesn't matter if you add more water. It will always be added at 350 ppm. If you were adding Trichlor then your CYA should have increased like it looks like it has but not your CH. Your CH should only rise above your fill if you were using Cal-Hypo shock. Of course your CH should not change from 600 to 275 unless you diluted the sample with lower CH ppm water. Since your fill is 350 then it should not go to 275 using your water. Unless it was raining (CH should be zero) and your pool water wasn't mixed and you sampled off the top?
When you refill your pool you should look into using low CH fill water. Trucked in water with low calcium or even run your water through a softner. One idea I had about reducing CH was to rig up a water softener type system. I thought about using like a tub filled with softner resin and drive a tube into the membrane to exchange the CH ions with salt. You probably could find an old tank on Craigslist and change out the resin in it and use it to fill with a simple hose. You should be able to fill about 2,400 gallons with a 48,000 grain water softner without having to regenerate the resin. So it would only take 1 regeneration for you to have 4,800 gallons of 0 CH water that should take your 350 fill water to 175 when you drain it in half.