Hi Tom, here's my 2 cents....
I installed a DG-220 about a month ago. First, I'd recomend ordering a Taylor (or Ben's) test kit that tells you your ppm of salt. I don't think you'll want to go to the pool store everytime you need to refill, after a rain, etc...
As for the calibration, hopefully Poolsean will see your post and respond. He's a great resource for all things Autopilot. You can also download the manual from Autopilot's web site.
After adding my salt and testing, I found the Autopilot showed about 300 ppm higher than the Taylor test (repeated 3x to be sure). I went to "Installer Menu" (hold it for 10 seconds). From there you can "callibrate" the salinity level, select power level, pump timers, etc. I just changed the Autopilot ppm down to match the test. So far, so good. Subsequent tests have been +/- 100 ppm, which is good enough for me.
For chemistry, follow the excellent advice offered here in the forum for your type of pool and all should be fine. I believe we are supposed to keep a higher CYA level than non SWG pools (60-80 ppm vs. 30-40 ppm). Unfourtunately, my pool was at 150+ when I checked it, and I've been replacing water to bring it down closer to 60-80.
Nater
16x32 Vinyl IG, 20,000 gal, Autopilot DIG-220 w/60 series cell, Dolphin Diagnostic Pool Boy
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