My fill water comes from a very deep (~600 ft) private water well. The water that it produces is off-the-charts high in calcium hardness. 127 grains/gallon the last time I measured it -- very tedious to count that many titration drops! So as you can imagine the CH of my pool is always quite high. And as if that is not challenge enough, the climate here is hot and usually very dry. This past month I've been using about 800 gallons of water/week to keep up with evaporation.
I do have a heavy-duty water softener, but I want to avoid using it for the pool. It costs me about 30 lbs of salt for every 700 gallons that flows through it (plus a regen cycle). And then I'd simply be trading CH for salinity build up over time.
I'd appreciate some guidance from the TFP experts on water chemistry targets I should be shooting for, given my unusual case.
I've been using PoolPal daily to help me with calculations and CSI tracking. Here's my latest measurements:
FC: I realize it needs to be higher per recommended FC/CYA ratio. Algae and clarity have not been a problem. The water's been great.
pH: I'm currently in the process cycle of reducing TA, so I've been adding acid to 7.0 nightly and running the waterfall continuously. pH rises to about 7.2-7.3 the next day.
TA: Was at about 130 after the last fill water top-off. Currently trying to reduce to 70 with good progress thus far.
CH: This has been very difficult to test with the Taylor K2006. I have a terrible case of the vanishing endpoint or whatever they call it. Even doing their special procedure of pre-adding the reagent, I continue to get a blue endpoint that seconds later turns purple. I expect the CH is higher than what I'm interpreting from the drop test.
CYA: Down from 230, yay!
Observed water quality: Fantastic. Very clear. No algae growth. No issues at all with scale.
Q: Should I strive for a lower pH to keep my CSI close to zero (balanced), below the norms recommended by TFP? What is the lowest I should ever allow pH to reach (assuming CSI is always balanced)?
Q: I'm wanting to add borates to 50ppm (test kit on the way). The sticky post on adding borates says to ask if CH and/or TA of fill water is high, so I'm asking ! What special procedures or conditions do I need to apply before or after adding borates?