I am not used to having low calcium right now FC 4.1, PH7.6, TA131, CH216, CYA43,csi -.04 temp guess of 70, new thermometer being shipped. Our area normally has tap water calcium in the high level to start out. Do I need to add more Calcium or is it alright with my csi. 15Kgal plaster pool and spa combo, DE filter, 1.5 HP at 70%flow for 4 hours. using 2 wheel phoenix with skim-a-long. Pool filled 9 days ago. Going back into a drought so I expect drain/fill to be outlawed again soon. right now using trichlor and 10% liquid to maintain chlorine level. Liquid chlorine is not always always in stock since Sept. Normally use HDX brand but lately only Leslies is avaliable for liquid chlorine. One filled Apollo floater, have not refilled yet. Leslies liquid M. Acid. Pool completely drained 10 days ago do to high calcium and TDS also had green south walls even with CH in 2 to 6 range . So far my Taylor readings taken every 2 or 3 days agree with Leslies tru blue tests when I go in to buy chemicals. I am using liquid chlorine to adjust chlorine level and Trichlor to try to maintain level. Pool is clear trying to keep from needing to change out the water as long as possible. Drain and Refill so far is cheaper than RO truck service $500 last I checked.