12,000 Gal pool
Jandy Aquapure 1400 SWG
Solar cover on, but waterfall on and spa spillover always on.
Heated to 88 degree F.
3 months old, just acid cleaned SWG last week (due to lack of Cl output....computer was keeping the cell in reverse mode trying to clean it....after acid wash, it was working fine....now goes in and out of reverse mode normally)
All tests below are with TF-100 kit
I noticed my FC levels were dropping often, even after the acid clean of the SWG. Checked CYA and it was 40. I confirmed water tests with local store (TF-100 matched up pretty close to the store testers).
I added 3 lbs of CYA 48 hrs ago. I also added 96 oz of bleach at the same time and a few hr later, the FC was about 7-8. This AM (which is aobut 36 hrs past adding both bleach and CYA), the FC was 2.5.
My SWG runs for 10 hrs a day and I have the SWG set for 80%.
So, after the above results, I ran the SWG for 12hrs at 100% to see what would happen.
This evening, (now 48 hrs since adding CYA), the CYA=80 on the TF-100 test kit (as predicted by chemgeek's spreadsheet ..thanks!). The FC is now about 3.
So I am a little concerned. I would have guessed that at 12hr of 100% output, the FC would be up more than just the 0.5 that I got today. This is not even summer yet, and I have the solar cover still on. I am not sure if 10 hrs of 80% output during the summer will hold the FC at the 4.0 that I need to keep it at.
My hopeful thought is that the CYA is still soaking up the FC and that most of the SWG output today went into the CYA buffer.
So I added some bleach tonight and I got the FC up to 5-6 range.
Does this sound resonable? Should I be worried? I think my SWG is working. The FC did go up, just not as much as I would have liked. Additionally, the pH is definately rising faster when I crank up he % output (pH was 7.5 two days ago, now it was 7.8...so I added some acid today as well.
Other labs....TA=90, ph 7.5-7.8 range, CA=350, salt 4000, no CC (all chlorine is FC), boric acid about 30-50 ppm, never had an alge bloom....and pool is crystal clear now.
Any thoughts? Thanks.