Combined Chlorine readings as a guide for need to Shock???

Oct 21, 2008
51
Terre Haute, IN
I was wondering if a pool user keeps the pool at the required FC level based on Ben's CYA/FC chart do you ever need to shock beyond season open/close?

More specifically, if one can keep the levels appropriare for FC and the CC levels stay below 0.5 is there ever a need to truly do the recommended weekly shock? I've read responses to other things in threads here and some indicated they don't shock. Can one use CC as a guide to when a shock is required??

Similar/related questions....Do facilities that have say 50K+ gallon pools ever shock their pools (due to cost)??? Or is the standard practice to just keep sanitizers at the proper levels and only shock when unplanned things happen to fix a problem???
 
I can answer both your questions because I have maintained commercial 55k and 60k gallon pools. The answers are the same. If the CC is below a certain level (.5 ppm for residential pools and around the same for commercial pools depending on state codes) then there is NO need to shock. As far as shocking weekly, a commercial pool with heavy usage will very possibly need shocking on an almost daily basis even with automatic chlorine injection using peristaltic pumps to keep the CC under control, along with daily or twice daily filter cleaning. Also, let's not forget the frequent fecal accidents from the toddlers in swim diapers, which are NOT designed to maintain an accident but only not to swell up when they get wet like regualar diapers do.
 
investindy said:
I was wondering if a pool user keeps the pool at the required FC level based on Ben's CYA/FC chart do you ever need to shock beyond season open/close?

More specifically, if one can keep the levels appropriare for FC and the CC levels stay below 0.5 is there ever a need to truly do the recommended weekly shock? I've read responses to other things in threads here and some indicated they don't shock. Can one use CC as a guide to when a shock is required??

Similar/related questions....Do facilities that have say 50K+ gallon pools ever shock their pools (due to cost)??? Or is the standard practice to just keep sanitizers at the proper levels and only shock when unplanned things happen to fix a problem???

Yep, you're correct - As a general rule, you can use CC as a guide for if and when your pool needs shocking, as long as your FC is where it should be for your given CYA level. As long as your CC stays at or below .5ppm and your water clarity is good, then you shouldn't need to shock your pool, and you definitely don't need to shock it weekly. I say this as a general rule because there have been instances where members of the forum have been shocking their pool and have had 0 CC, but were still losing FC overnight, so they had to keep shocking the pool until the overnight FC loss stopped (I think that was a case where the FC was still battling algae, but the algae wasn't creating any CC's). My personal experience is that I use CC as a guide, and shocked my pool maybe three times this past season; opening, once when I got lazy and didn't keep an eye on my FC, and at the end of the season when I closed the pool.

I can't answer the question about the larger facilities and how they sanitize their pools, but I'm sure some of the folks who work in the industry could answer that.

EDIT: The 'Bear beat me to it! :lol:
 
THANK YOU GUYS SO MUCH FOR THE REPLY!!!!!!! Also nice to know MikeInTN that there could be scenarios where there appears to be no CC and high FC droppage requires a shock to fix....I may of been on here in the future without being armed with that extra contribution.

MikeInTN and Waterbear......Privilledged to get responses from you guys over this. I've read your guys responses in other threads and am impressed with your knowledge and eagerness to help other pool owners....Thanks for the time on this thread and all the threads you contribute to, I've learned A LOT the last month on TFP!!!!!!!!!!!!!
 
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