So how come there aren't a LOT of sick people?

[bbb]

Actually you need more! The cell instantaneously generates a high concentration of chlorine that destroys the chloramines AT the cell.

If there was not a high CYA level, most of it would be used up before it got into the pool proper. The alternative would be to run at high chlorinating outputs, resulting in rapid reduction of cell life.

Hope this helps.

Pat

:lightbulb lighting over head:

Thanks, Pat. This is about the 10th time I read that if there was not a high CYA level, most of the SWG-produced chlorine in the cell would be used up before it got into the pool proper - and I finally figured it out -

Without the added CYA, the superchlorination at the cell is TOO effective, so, under higher bather load or organic contaminant conditions, there isn't much unused FC left after the water passes the cell and goes toward your return!

With additional CYA present (say 60-80 ppm), there is a little less superchlorination at the cell (because chlorine is less effective per PPM with CYA present), so there is more residual left as the chlorine passes back into the water into your pool, where it can fight contamination of the water actually in the pool and (keeping this sort of on topic), preventing people from getting sick from stuff in the pool!

Finally, because there is still effective (just a little less powerful per PPM because of the 60-80 ppm CYA) superchlorination going on in your water because the salt water generator cell is operating, you should be able to run with a (slightly) lower amount of FC residual in your SWG pool than with a pool chlorinated in batch form (like bleach or cal-hypo) or drip form (chlorine feeders, trichlor pucks) for your given level of CYA.



ps - the "benefactor or bomb" article is very good but needs to be taken with a grain of salt (whether or not you are running a SWG! ) PoolDoc has excellent comments elsewhere on the forum about it - here is the link. CYA is NOT "bad" -- running your pool with too much of it and not enough chlorine (like anyone using a constant amount of trichlor pucks in a feeder all year, and using a test kit or strip that only counts to 5 or 10ppm of chlorine) IS "bad". It's that simple. And for people who have very sunny pools (aylad comes to mind), CYA is a huge help. My pool isn't that sunny, but when I cholorinated exclusively with bleach last year, I chose a higher CYA rate so I could add bleach every other day instead of every day. And now that I have an SWG, I am slowly increasing my CYA from 35 to (probably) around 60.

My understanding: with the addition of common sense and real-world experience to the "benefactor or bomb" material, you get Ben's "Best Guess" chart.