I know that preferred chemical for shocking at this forum is liquid bleach. Right now the cheapest bleach I can find is 6% 1.42 gallon clorax at kmart for $3.49 (can't find ultra). for 27k gallon pool to introduce 10 ppm for super-chlorination i would need 4.5 gallons of bleach, which would run me about $16.
the alternative would be cal hypo. leslie's sells their power powder plus shock for $3.15 per pound. and they claim it would treat up to 16,5k gallons. at that rate, the same shocking would cost me only $5.15. i find it strange that they say it would treat 16,5k gallons of water. their product is regular cal hypo, and the latter should treat 7.5k of water for 10 ppm introduction or 10k of water for 7 ppm. even taking the lowest number (7.5k), it would cost $11.35 which is still cheaper then bleach.
so it seems something doesn't add up. 2 question:
1. is my math off somewhere or how do people get cost effectiveness of the bleach?
2. why 16,500 gallon number instead of 10,000?