Still new to this... my pool pump motor died a week ago. I finally got a replacement on Monday, installed it Monday night and ran the filter overnight. Suprisingly, the water was still crystal clear with no signs of algea, even after having the pump off for almost a week. I did put several chlorine pucks in the floaters, but that was it. When I started the pump, I immediately noticed that "chlorine smell" that I know is caused by the chlorine reacting to stuff in the water. Also the water in the skimmer boxes had a bit of slime around the edges. We are having a get-together this weekend, so I didn't want to take any chances. I dumped in 5 gallons of 12% liquid sodium hypochlorite just to be safe.
Now the weather is going to be almost 100 degrees and my chlorine levels are way up. As of this morning, my levels were: FC 23; CC 0. With a CYA of 40, the CYA chart says shocking level is 16. I've read that anything above shock level is not safe for swimming. I wouldn't care, but I don't want my wife or two-year old son in the pool unless it is safe.
Anyway, I've read that you can use sodium thiosulfate (sold at Leslies; $12.99 for 3 lbs) to lower chlorine levels. From what I've read, 2.5 ozs. of sodium thiosulfate for every 10k gallons of pool water will lower chlorine levels by 1 ppm. My pool is 30k gallons, so if I added one container (3 lbs), it should lower my chlorine from 23 ppm down to roughly 16 ppm. Also, we're supposed to get full sun today, so that should lower the levels as well.
Any downside to using this stuff? Also, do my calculations look right?