FC rose from 6.5 to 13 in 3 days with no chemicals added. How? Hose water or SWG?

just4747

Well-known member
May 20, 2024
67
CT
Pool Size
12000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
My FC tested at 6.5ppm 3 days ago and now it is testing at 13 or 13.5. I haven't touched the chemicals at all and we have a SWG running at 40% whenever the filter runs. Normally the filter is run from 9am-4pm daily unless I need to circulate water longer or overnight.

The only two factors over the last 3 days that may contribute are:

1. I've been using our hose water and spraying thousands of microscopic springtails into the skimmer port over the past 2 days - lots of random spraying of the pool surface water towards the skimmer on and off.

2. Because of the springtail issue I've also been running the filter overnight 24/7 for the past 2 days and that includes the SWG at 40%.

I wouldn't think that the FC would rise this much due to the constant running of the SWG but would it be due to this even if I haven't changed the 40% setting?

I'm also guessing the hose water entering the pool shouldnt cause the FC to rise that much or at all but thought I'd mention it just in case.

Thanks.
 
At 40% for 24 hours you make about 5.6 FC. You're probably only losing 3 per day, so it makes sense it climbed. I LOVE these problems because we are *not* discussing your swamp. Keep up the good work and make sure to only dial it down a little, remaining free and clear above min.
 
At 40% for 24 hours you make about 5.6 FC. You're probably only losing 3 per day, so it makes sense it climbed. I LOVE these problems because we are *not* discussing your swamp. Keep up the good work and make sure to only dial it down a little, remaining free and clear above min.
Thanks! Yeah I will shut off the generator and test every day till it normalizes and then back on.

Ha I agree - I'm glad these are the issues I am having vs some crazy algae problem or something :)
 
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You've added 17 hours of FC production each day.
Yeah I figured this was the cause but just wanted to confirm. Do you think swimming in the pool with this FC level for a day is ok? My level should be btw 4 and 9 at my current CYA.
 
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You're safe and you'd never know what the FC is swimming between min and SLAM.

swcg_chart.jpg

Allllllllll that leeway above target is your friend. There is very little leeway below target. One whopper of a storm, a particularly high UV day, the Spouse plays hookey and has a swim day with the kids...... bad things happen when folks cut the line too close.
 
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*case and point. On a Monday night, with no warning, there are 6 older teenagers having a blast out back right now.

Maybe my FC was a 9 after the hot and sunny day, maybe it was an 11. It doesn't matter either way, I was covered for the scorcher and the impromptu party.
 
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You're safe and you'd never know what the FC is swimming between min and SLAM.

View attachment 596335

Allllllllll that leeway above target is your friend. There is very little leeway below target. One whopper of a storm, a particularly high UV day, the Spouse plays hookey and has a swim day with the kids...... bad things happen when folks cut the line too close.
Thanks!
 
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