Quote Originally Posted by Water_man View Post

"Traditional" pool procedures recommend shocking every week. From what I understood so far, as far as you are concerned, the only thing that matters is if CC >0.5.
So suppose, my pool goes on CC <0.5 for a long time, and there's no other visible organic contaminant as pollen or suntan lotion film, I don't need to shock?
Pool chemical companies (Arch Chemical is a prime example) are the ones that recommened shocking weekly ( and with a product labeled as 'shock') This just helps increase their bottom line (BTW, Arch Chemical is one of the largest cal hyp manufacturers and the vast majority of it they sell as 'shock')

Shock when the CC is above .5 ppm, the reason for this is that the threshold level for the majority of people to detect CC is .4 ppm but , unless you are doing a high resolution FAS-DPD test or a liquid color standard DPD test it is impossible to detect this small a change. Most DPD color comparators in home test kits can only measure .5 or 1 ppm of CC accurately (and only if you have good color recognition for shades of red, which many men have difficulty with. It is much easier for women).

If your FC is holding, Your CC is .5 ppm or lower, and your water is not cloudy then there is no need to shock. However, if you just had a big pool party and the pool had a much bigger bather load than normal, then shock. If it just rained heavily, then shock. If the pool looks cloudy, then shock. It's really just common sense.