Been having a bit of a mystery with my SWCG. It's a Jandy Aqua-Pure 1400. Three weeks ago, I was humming along quite nicely with a 30% setting on the control unit and salinity of 3300 yielding right around 4.5 ppm FC -right where I wanted it. Had this steady-state for several weeks prior, and chems were about as they show at the bottom -about where I want them.
So we had a couple of big rains for which I dumped some water out to waste to get the water level right, and then later, a lot of swimming/ splashing/ evaporation, for which I added a bit of water. So my Salt level dropped to 3000 ppm, I shoot for 3300 so I added the right amount of salt to get that level right two days before vacation. The morning I left for vacation the salinity was right at 3300, 30% setting on the control unit and a FC of 4.5 -happiness and light!!
I got back from vacation a week later and my FC had spiked to 9.5 -everything else was in-line (+/- as below) so I bumped the control unit down to 20%. Testing 3 days later the FC was 10.5 -wrong direction!! So I bumped it down to 15% and figured there may just be latency in the SWCG so I'd give it some time. That was Tues. It's been running at at 15% since then, we've gotten some rain and I had to dump a little water yesterday, but otherwise nothing else has changed. I added no salt and only the requisite amount of MA to keep pH in check.
I just tested and my FC was 10. So I set the control unit to it's lowest setting: 5% and I'll test again on Sun I guess, but it really is a bit of mystery to me. Every time I bump the control unit % down precipitously I keep expecting to see abysmally low FC level all of the sudden, but It's not happened. I'm a bit perplexed.
I run my pump 24/7 so I guess that could influence things, but that has not changed -so, why did I have an apparent steady-state @ 24/7: 30% for several weeks before vacation?
I use the salinity tester built into the Aqua-Pure control unit to test salt levels -perhaps that's a factor??
Could the control unit be acting up?
Could having added salt be influencing things?
My numbers as of tonight (TF-100):
pH: 7.7 -added MA
CYA: 50 (Jandy recommends 50-80 ppm)
As always, help is appreciated.