We have had our IG vinyl pool for about 1.5 months now. It has an SWG.
Its approx 14,500 gallons.The first few weeks it saw moderate usage and we had to keep adjusting the pH levels down, so far normal. Now the past 1.5-2 weeks the usage has gone down to light, maybe 1 swim every 2 days average and light bather load. The SWG is normally set at 60% but I have managed to get away with 40%. In any case the chlorine levels seem to be going up. Tested it with my kit and its always off the chart now 5+, before it used to be in the 4-5ppm. The real question is that the pH seems to be stuck at 7.1 - 7.2 and hasnt moved in 2 weeks. Is it because the bather load is lighter and the weather is cooler, we do tend to keep our solar blanket on, even during the day if no one is using the pool. The last test was
CYA 30
FC 5
CC .2
alk was 180
pH 7.6,

but that was about 2.5 weeks ago. I have dropped the SWG to 20% and I am planning to bring the water in for test tomorrow. Never thought i may have to raise the pH with an SWG.