First, since this is my first post, let me just say thanks for creating such an awesome site! The pool school section is great for pool noobs like me. I just wish I knew about it and read it BEFORE I set up my new Intex pool and Intex SWG (model CS8110, the one with the copper ionization). Second, sorry for such a long post. Jason wanted data, so I'm trying to be thorough.
I filled the pool a week ago from our city water and this town is famous for having haaaard water. Anyway, I followed the Intex directions on setting up the pool and the Intex directions for setting up the SWG. The directions basically say, add 125 lbs of salt to the water (I saw a recommendation that you start by adding 75% on the Intex site, so I only added 100lbs and the generator seems to be producing CL with no error messages), wait 24 hours then turn on the SWG, set it for 4 hours, and run the "boost" mode (which runs the SWG full tilt for 4x the normal time, so 16 hours in my case) on the SWG to shock the pool. Well, after "boosting" the pool the first time, I didn't have any FC or TC (measured on sticks), so I set it to run for 6 hours the next night and no FC or TC again. I set it to "boost" again (so this time for 24 hours) and little to nothing the next day.
We've had great weather here and the pool has had bathers almost every day.
I was starting to panic, but the SWG was making bubbles and when I put a stick up to the return it did register FC and TC, but after a week I couldn't get it to last in the pool. Then I started doing research, and read on another site what CYA was, so I went and bought some (100% granules) today and added enough to the pool to get it up to 30ppm. I also saw that test strips were junk, so I bought the HTH 6-way test.
As I was doing that I noticed one edge of my pool had the slightest tinge of a brown ring up at the water line. The water is still crystal clear and not slippery or anything, but my neighbor last year had his water turn green twice (almost instantly) and had to refill, so I added 5 ounces of "Leisure Time Simple Spa Care 56 Chlorinating Granules" (Sodium Dichloro-s-Triazinetrione Dihydrate 99%) that I happened to have lying around (I don't have a spa, don't ask).
OK, so now the current facts:
pH - 7.2-7.5
TA - 220 ppm
FC - can't test
TC - 2-3 ppm
CH - 240 ppm
CYA - should be coming up to 30 this week with the CYA I added today plus some from the spa 56? I only get to test it one more time with this kit, so I'm waiting for the acid to dissolve.
So, what should I do to lower the TA and CH without tanking everything else? I have read that I can use Muriatic acid with a SWG, but not Dry acid. The pool calculator tells me I should replace 79% of my pool water with new 0 CH water, but that won't work for me as our water is hard from the tap.
Also, Intex recommended a CYA of 10 ppm, all the sites I have read say at least 30 ppm, and many SWG people seem to be running much higher, like 60-80 ppm. What should I do? I have plenty of CYA if I should add more.