Help with daytime FC drops

[Hutch12]

Hey guys... this year was the first time I've had to slam my pool and was wondering if this is normal.

Basically I had a period in time earlier this year where my cartridge filters needed to be replaced because there wasn't enough flow to engage my SWG. I didn't notice this for a few days and left the auto cover closed. When I opened my pool the normal crystal clear water was now a cloudy mess. SLAMed the pool for a couple weeks and was finally able to get my night time FC loss to less than 1 FC without the swg on. However, even with the swg on now during the day, I'm dropping 5-7 FC. I'm afraid to let it go lower in case I still need to slam. I'm still losing less than 1fc at night but daytime consumption with no swimmers is crazy. Is it normal to lose that much when FC is that high?

I know my swg is working, at night it will climb 5 or more FC if running.

Current stats

FC 15
CC .5
PH 7.5
TA 170
CYA 70

 

[woodyp]

How long and WHEN are you running the SWG at what percentage?

 

[Hutch12]

Wasn't running it during the SLAM or during my night FC checks. Running it at 20-40% during the day when the pump is running for around 13 hours a day. Just like I did previous years without issue

 

[Hutch12]

For example, this morning FC started at 13 and now it's down to 8, 13 hours later. Pump on the whole time and swg at 40% . Is this normal drop or am I going to be 0 FC in a few days if I do nothing? The pool does receive all day direct sun. I have never checked this frequently before because I've never had an issue before so I have no idea if this is normal. I wouldn't think so with my cya within proper levels. I will add that the water is still crystal clear. It does receive direct sunlight the whole day

 

[pooldv]

Normal FC usage is 2-4 ppm. Something is up. When is the last time you tested CYA? Was it sunny, back to the sun, etc? Is the water clear? I would be inclined to run FC up to 10 and do another Overnight Chlorine Loss Test. And then keep FC up for a few days just in case something is brewing. Maybe a flock of birds made a special delivery or something.

 

[Hutch12]

I checked this morning, and overnight with the pump off I lost one FC (down to 7). I upped the percentage on the SWG and closed the auto cover today and will report the change when I get home. Water has been crystal clear since day 2 of the slam. (I SLAMMED for about 7 days)

I just checked CYA late last week, it was early evening, not directly in the sun. I will check again tonight when I get home.