I have just recently discovered this and the PF site and begun educating myself on pool chemistry. Until now, I've just relied on the advice of my local pool store.....now that I understand more about what's actually going on with my water, I'm not sure I was getting good advice.
In any case, I live in southern Arizona and I have a 'special needs' pool because of my unique bather load. I am a nationally certified survival swim instructor and I have anywhere from 15-30 infants and small children in my pool EVERY DAY, ranging in age from 6 months to 6 years, all within a 2 to 4 hour block of time.
I had my water tested on Monday and here's what I had:
I have a 22,000 gal inground plaster pool with attached spa, sand filter, corona discharge ozonator, solar heating & solar blanket. I keep the water temp between 85-88.
I now know that based on my CYA level, my FC needs to be WAY higher than it is and have been adding the granular chlorine (calcium hypochlorite) to raise the FC. My FC is now around 7ppm.
Here are my questions:
Can someone tell me why high CYA dictates a higher level of FC? I don't understand that relationship....and my hubby is skeptical.
I JUST purchased a 50 lb. bucket of trichlor, and have read that trichlor is bundled with CYA, which will cause my CYA to go even higher.....is there any way I can continue to use it with my already too-high CYA? The label says it is 99% trichlor, 1% other, and total deliverable chlorine is 90%. I'd sure hate to shelf $150 in chlorine...
In looking at my also brand-new 50 lb. bucket of Bioguard CLC2 (what they sold us to use to shock the pool), it's calcium hypochlorite 47% and other ingredients 53% and I'm wondering if there are any CYA or other issues with that product that I need to be aware of...
I've also been following the store's dosage instructions for shocking with the CLC2, which is 1 lb per 10K gallons, so I've been using 2 lbs for my 22K gal pool. How long does the FC need to remain high in order for the "shock" to occur? Is it just that it needs to get up to that level, and then I can let it go back down, or does it need to stay there for a period of time? I read somewhere that with my CYA, I need to obtain 25ppm FC for shock. This seems like a scary high number to me. How long do bathers need to stay out of the pool at that level, especially considering that most of my bathers are 4 and under??
Any other things that I need to know about, given my unique bather load?
Thanks to any and all that take the time to reply! I'm finally beginning to understand the chemistry and it's nice to feel like I might be in control again...