UPDATE 2,391: After my problems returned again, I didn't do a complete SLAM as I had no idea what the issue was.
First, I brought my salt level up to 3,600 from 3,100, which is Pentair's recommended level. Next, I used Orenda PR-10,000 to remove the 390 ppb in phosphates I had. After a few days, I wasn't rapidly losing chlorine but wasn't really maintaining either.
Finally, I plugged my autofill. 2 days later, my chlorine went up 3 ppm with just SWG use. After another 2 days, it went up another 3ppm. First time this has EVER happened!
I have TONS of sulfur in my water and the auto fill sits directly in the sun - the canister water is typically 100 degrees. The only thing I can think of is that the sulfur just festering in there is interfering with the pool chemistry. That's all I've got to go on at this point.
Additionally, my PB said they're coming out to install an IC-60 vice the IC-40 that is currently being used. This should just make the whole situation better.
Thanks again for all your help! So thankful for this forum.