Does anyone have a DI meter built into their RO/DI?

[FragIt Dan]

Are you talking about a TDS meter? I don't know of anything that will measure ions in general. If you still have phosphate post DI, slow the water flow down or change the DI as it may be exhausted. DI works based on exposure time, so if you have a reservoir you need to put it after the DI and put a one way valve in between the DI and the reservoir. Used properly, you should be phosphate free.
Dan