OTO and CYA and TC, oh my! What's being measured?

[mwsmith2]

Okay, got it.

I'm actually trying to run the pool with very low CYA (about 10ppm) so I can also run relatively low chlorine - 2-3ppm

With 10 ppm cya, i wouldn't consider 2-3 ppm "low chlorine". I'd consider that "normal chlorine", and for you cya level, it might even fall into the category of "high chlorine". I think you need to do A LOT more research on the chemistry, along with the hazards of a pressurized chlorine feed system before you go any further. There are MUCH safer ways to do what you are doing.

That's just my $0.02.

Michael