I have an 18000 gal. IG pool/spa combo that has been running a week. Until I a m allowed to start my SWC in a couple months, my basic plan on the Chlorine front was to keep a couple of 3" pucks in a floater and add a gallon of 12% chlorine once a week to shock. According to the bleach calc (nice little tool!), a gallon of 12% would be just right for shocking purposes. However no where can I find a formula for how many trichlor tabs to use at once. The avg. water temp is right around 85 degrees. So far my Ph is holding steady at 7.6, though I believe I am right on the edge of going to 7.8. TA is always 90. Is it too early to worry about Calcium hardness and TDS? Until I get my new kit I won't know how much CYA the pool guy added at start up. Thanks!