I'm 18 months in to my new pool and have watched the CH rise from just over 400 (14 months ago) up to today's high of 620.
I believe it's time to partially drain and refill. That being the case I have three questions which I could do with a few pointers on:
My CH is 620 now and my fill water has a CH of 120. Do I just go for an easy "half the pool" and hope that I end up around CH 365 after refilling or do I need to be more ambitious?
What do people do for pumps? Is there any way I can use my pool equipment to pump this out? I could go and buy a cheapo sump pump from Lowes for about $80 or go and rent a trash pump from Home Depot for the day for about $50?
What causes my CH to rise? Is it a CSI of <-0.3 pulling Calcium from the plaster or a CSI of >0.3 about to dump it all over my plaster? I think I am completely misunderstanding the whole CH thing but please take the question in the ignorant spirit in which it was intended!
Thanks for your support TFP team (as ever!)
Borates 40(ish, it's between 30 & 50 on the test strip)