Hey MisterGreen- This sounds like another really cool project. If the science involved can be sorted out and a fairly accurate prototype built, maybe we can build a "Close enough Ph Controller" too.
225 Gal, Glass "Reef Ready" w/ twin Iwaki Pumps & 2 Ocean Clear inline filters. Custom 320 watt LED Lighting system w/ BlueFish "mini" Led Controller,iAqua Aquarium Controller
, and a 20lb CO2 system w/ Milwaukee Ph Controller.