Just following up--using a ph setpoint of 7.6 really reduced the required acid. Only a quart or two since the post and pH is tightly controlled by the Intellichem system, at least when the pump is running (it always is, and has been for a while when we are in the pool.
For what it's worth, chlorine demand also continues to be quite low while maintaining ORP > 700.
We've never noticed any harshness or swimsuit deterioration over the last 4-5 years. Maybe because that's because we're never in the pool more than an hour a day. (Or maybe we just have tough old skin and swim alot without suits!) but for whatever reason, it's not an issue for us.
I've always gone with 0 CYA. The problem I have with adding CYA is that I can't take it out, and I'm quite happy with having none. ORP probes are more sensitive, and much less FC is needed for the same sanitation level. Less chlorine means less to be destroyed by sunlight.
Yes, I recall some anecdotal stuff about the CYA somehow shading/shielding to result in lower chlorine usage, but, again, I'm really happy with the small amount I've been using for several years.
Thanks again!
Thanks again.