I inherited a pool maintained by a pool service. Last December I had to dump half the water to get CYA down. Again, this month I had to dump about 2/3 of the water to get rid of CYA that apparently was in the pool walls and pipes.
I have had it with stabilized dichlor and trichor, have removed the floats from the pool, and am moving to liquid bleach as recommended on this forum.
Here are my test numbers as per a Taylor test kit following refilling and running the pump for 24 hours (and adding about 200 oz of 8.5% bleach late in the afternoon):
FC - 0
CC - 0
CYA - 55 (down from 150)
pH - 7.6
CA - 270
Tot AL - 70
25,000 gal in-ground plaster pool
Pool is crystal clear and beautiful.
With the pool now refilled, I cannot seem to hold any chlorine in the pool. If I add a jug of bleach, the FC comes up but a few hours later, nothing. I am just assuming the chlorine is being used up by organisms in the new and remaining old water. ???? Otherwise, where is it going?
The Taylor book recommends shocking the pool to 30 when the water has been changed. This will require, according to the pool calculator, about $30 of bleach for this one supershock! That seems excessive to me, since I am not combating high CC and doing breakpoint chlorination.
Can someone recommend what level of chlorination (ppm) I should shoot for to shock the pool? I can use the calculator from there.
Also, how much hypochlorite (jugs of liquid bleach 8.25%) should I anticipate needing each week given light usage of the pool?