CH and Saturation Index - should I care?

[sande005]

I'm ready this year to fully jump into the TFP recommendations after dealing with my pool for many years. Have always used a Lamott tablet based test kit, with the slide type comparators (not the electronic gadget). It's old, but I have a healthy stock (unexpired) of tablets still. Have followed their guidelines for everything. One of the tests involves measuring CH, and then using their "slide rule" to interpolate against TA to come up with a Saturation Index. Strongly recommended to monitor many years ago by my dealer to protect my heater core.
CH levels in the spring are always low to very low. Currently 120ppm. Not relishing having to go on the hunt for bags of Calcium Chloride - hard to find, and I need 35-45 lbs every year to get into a range of 250-300 recommended.

Reading here that it is not really something to be concerned about with a vinyl pool. Can anyone expand on the subject?

 

[duraleigh]

What is the CH of your fill water?

 

[sande005]

Right now fill is 140, I've seen it as low as 80.

Pool traditionally pumped to a a couple of inches below the jets for closing. This year snow and rain filled it to within an inch of the coping (!) when I uncovered. Also have pumped to waste and refilled 6 inches a couple of times to get all the winter gunk and dead algae out, and one rain/hail storm that overfilled it 4 "
Currently:
7.6 ph, 70 Alk, 150 CH, 10 Cl (shocking it), <20 CYA, Temp 60F
Shopping for a Salt system, may not happen real soon. Using 3" Tri in the feeder (but at this temp, doesn't feed very heavily), and 12.5% Cl liquid. Thinking about Borax.

 

[sande005]

Just saw this under the handy "similar threads": Calcium Hardness, vinyl liner, saturation index, gas heater
So sounds like if I keep my pH under control, the heater will be fine. Should I be shooting for ~250-300 (my old target) in hopes that a bit precipitates in the heater to act as a protective coating?

 

[duraleigh]

With 140 CH fill water, I might be tempted to leave CH alone and let it rise as you add fill. If yours was a plaster pool, I would suggest going ahead to bring it up using calcium chloride but, in a vinyl pool, CH is just not that critical..