switch from dichlor to bleach?

[minsx]

Hi! I've just set up a new intex Easy Set and have REALLY appreciated the info posted on this site and the 'kiddie pool care' info post.

I have also spent some time at Trouble Free Pool and I have gleaned a lot of information from their 'pool school' as well.

I was curious about CYA buildup based on the method posted here: http://www.poolforum.com/pf2/showthr...p-routine-care.

As I understand it, with high CYA levels, higher amounts of chlorine are necessary. Is it a nonissue because with small pools its assumed that splashing and drain/refill as part of maintenence?

[chem geek]

The "dose" of one cup of Dichlor per 6000 gallons is around 5.5 ppm FC and increases CYA by 5 ppm. If that were done for a month, then without water dilution the CYA would increase by 150 ppm, but the dosing is fairly high so the FC may stay high. Also, at the first sign of algae, the pool is dosed with 22 ppm FC worth of bleach. Finally, the pools are temporary and the volumes are low so water can be replaced rather easily. Nevertheless, the buildup of CYA is why the other temporary/seasonal pools approach you mention uses a Dichlor-then-bleach method similar to what is done in spas/hot-tubs.

I think once things are initially set up, the daily chlorine loss will only be somewhat higher than regular pools. There will be the roughly 2-3 ppm FC per day lost from sunlight (though that will drop as the CYA level climbs) plus an additional amount in the smaller Intex pools from bather load, perhaps another 1 ppm FC or so (figure around 1 ppm FC in 1000 gallons per person-hour of being in the pool where larger volumes are proportionately less).