Phosphates? High CYA!

[onemsmom]

After the pool company owner came out and saw that the CYA really WAS that high, he agreed to a partial drain & refill. After talking to him, it seems an employee probably shot the CYA really high & skipped a few visits. He had similar issues with other clients and employee has been fired. With all of that said, my pool is still green ( I was away for 2 weeks), the CYA is still too high (90ish) and the chlorine is at 1ppm. Ugh. So he is obviously not dealing with the problem properly and I will take my pool care back into my own hands. I STINK at being consistent, so this is hard for me, but I will do my best.

I have forgotten how much bleach raises 1 ppm for my pool - could you please refresh my memory? I think it was 1/2 bottle = 1 ppm, but I'm not completely sure. I'm a 24' round - above ground - 13,000 gallons (I think).

Here we go again.

Thank you,

Jennifer

[kelemvor]

In 13k gallons of water, 1 gallon of 6% bleach will give you 4.75ppm. So if your bottle = 1 gallon, 1/2 of that bottle gives you about 2.4ppm. At 90cya you need to be over 20ppm to shock.

This is based on the best guess chart and your 90ppm cya. You need to KEEP it above 20ppm and keep testing for combined chlorine until your CC is 0, and you don't lose more than 1ppm FC between sundown one night and sunup the next morning.

Once that happens you can let it drift down to 5-10ppm for regular operations. I keep my pool at that level of CYA (because my swcg recommends that level) so you can definitely run your pool at 90ppm cya.

If you're not diligent enough to maintain things on a regular basis - and don't have a metal pool - then you might want to consider a salt water chlorine generator. You still have to stay on top of your pH (I usually dose with acid about once a week). A swcg won't help you clean up the mess though; you're going to have to do that the regular way.

[onemsmom]

Thank you so much!

[onemsmom]

Question - would adding extra bleach buy me more time between checking/adding or make this process go more quickly or would it just waste bleach? Ex. if I'm supposed to keep the level above 20, would it speed things up to keep it above 30, etc.?

Thanks,

Jennifer

[chem geek]

For shocking, a higher FC level makes things go somewhat faster but the chlorine losses from sunlight are greater since they are based on the percentage of FC. However, speeding up the algae kill isn't the slowest part of the process. The slowest part is then removing the dead algae via filtration.

As for regular maintenance, starting with a higher FC level will have it last longer, but because it drops as a percentage of FC you will be using more bleach. It's not "wasteful" so much as a trade-off between convenience of not adding chlorine as often vs. the extra cost associated with the larger amount of bleach that is needed.