Here is update #1: (Sorry, it's long). I only found 2 options for chelating shampoos where I live. 1) Ion Hard Water Shampoo. 2) Quantum Clarifying/Chelating Shampoo. I decided to go with the Quantum.
My procedure:
1) Oiled hair generously with coconut oil the day before chelating, and bunned overnight (since I expected a chelating shampoo would be very drying).
2) The next day, rinsed with reverse osmosis filtered water, applied Quantum chelating shampoo only once, massaged in for about 2 minutes, rinsed.
3) Deep conditioned with Phytojojoba mask; wrapped hair in saran wrap & plastic cap; used bonnet dryer on medium heat (I never use high heat) for 1 hour. Normally I only do 30 minutes. I let the DC remain in my hair for 3 more hours without heat.
An unusually long DC treatment for me!
4) Rinsed with filtered water & applied a protein leave-in conditioner for balance (since my DC was a moisture treatment). On top of that I liberally applied a leave-in with
lots of slip for easier detangling, since my hair still felt dry after chelating. After detangling I applied CHI Silk Infusion, Nexxus Heat Protexx, and coconut oil.
5) Air dried in a loose ponytail, then bunned.
6) Applied more coconut oil to my ends and flat ironed at
140 degrees Fahrenheit with only 1 pass (for smoothing and sealing, not straightening).
Note: Normally I only do this on haircut days since I'm afraid of all direct heat but I've recently made a discovery: I'm surprised to find that by doing this I have less breakage than when I air dry only, since it keeps my hair smoother & tangle-free until the next wash day. But I will research this further before incorporating any direct heat into my regular routine.
My initial observations after 1st chelating treatment:
1) My hair is a bit dry, but softer & shinier with more body (probably due to #2 below). The ends don't feel as rough as before.
2) My DC treatment seems to have worked better.
3) Surprisingly the chelating shampoo didn't seem to dry out my hair more than clarifying poos or some of the harsh sulfate poos that claimed to be "moisturizing".
4) After a few applications I think the Quantum chelating poo
should be able to effectively remove several years of hard water mineral buildup. Plus it's what I had available here. But since it is so stripping on my fragile hair (it has sulfates and sodium chloride) I will explore the milder options suggested in this thread, for future use.
5) It is too early to determine how much the thinning & breakage issues will improve, but I'm hopeful.
Below is a photo after my 1st chelating treatment. It looks dry but definitely feels softer, has more body and is shinier than before treatment.
Thanks again ladies, for your tips and advice!!!