Re: Free Chlorine vs. Total Chlorine adjusting
Originally Posted by PoolDoc
I read the links you posted in another thread about the bacterial degredation of CYA and realized that they are the same families of bacteria that are used for anerobic denitrification (a good thing!) in a salt water aquarium (and also in soil). Under dark, anerobic conditions such as a covered pool with no circualtion, it is possible that some of the urea and ammonia are broken down all the way to NO2 and N2 which can gas off out of the water, laving less urea and ammonia compouds to form CC. In aquariums the breakdown cycle (simplified) is nitrate to nitrite to ammonia (and possibly other ammonia compounds), to NO2 and N2 which leave the aquarium water. Becuase of the chemical structure of CYA (and my limited chemistry knowledge) it seems that breakdown to urea is most likely. I don't know if it is more perisitant than ammonia but I suspect it is. This probably also affects the breakdown products as well. I don't really know at this point just how urea will be degraded by the bacteria but I belive it eventually follows the same pathway.
This is just my thoughts based on my knowlege of the process in aquariums and I intend to research it more as time permits but it is a possible explanation to watermom's question.
11.75'x23.75' kidney 6.5K gal IG fiberglass pool/300 gal acrylic spillover spa combo; Aqualogic automation/SWCG; Pentair Clean and Clear 150 cart filter; 1.5 hp uprated 2 spd Pentair Whisperflo pump; PF:17
Retired pool store and commercial pool maintenance guy.