Cannot maintain FC levels w/ BBB

[Slachey]

Watermom.

I am not posting on both forums, I simply did a search for calculating bleach quantities, and that came up. I will use your methods in the Best Guess Chlorine Chart. As there are "ranges" of FC on the chart for "ranges" of CYA, what normal FC range should I be in for a CYA of 90-100?

Thanks again for all of your assistance. Yours and others experience on this forum are invaluable!

[PoolDoc]

There are no absolute ranges, and the data and analysis has continued to develop since I first published the 'Best Guess" chart nearly 14 years ago. Currently, we're not completely sure what happens at very high levels of chlorine, even when the CYA is also very high. It doesn't seem to be a problem for people -- over the past week a local 200,000 country club pool I service has been at CYA=~100 ppm and FC=~25 ppm, with no complaints or problems.

But we're still not sure that a level like CYA=100 and FC=40 won't bleach suits or liners, though we're pretty sure it won't be a problem for 90+% of swimmers. We do KNOW that it's not dangerous, because bleach baths (CYA=0, FC=50 - 100 ppm) have been used by dermatologists for years to treat both adult and pediatric patients.

[Slachey]

Thanks PoolDoc. So would I be safe in a FC range of 8 - 12 for normal everyday use or would you go lower?

[PoolDoc]

With CYA=100, FC = 8 - 12 ppm would be fine.

If you were in an arid region, and using a DE filter, you could probably go lower. But in Pennsylvania, you'd be risking algae if you did so.

[Watermom]

Please don't think I was 'fussing' at you ------ I wasn't. It's just hard to mix and match advice from multiple forums. I hope that we have been able to answer your questions.

Let us know how your overnight test goes tonight.