Thanks to @Rockwood for the motivation. I bought the pressure washer on amazon based on the reviews there. The filter and DI system I bought from the oem.
I took the factory plastic piece off and juat atarted figuring it out with scrap I had in my scrap bucket.
I'm going to do some TDS testing this afternoon when it cools off a bit.
Update: when the pump would turn off it would send high pressure spike backwards through the tube to the 2 way valve and blow a hole in tthe tubing. I tried adding a water hammer dampener but it did not work.
I bought a check valve and plumbed it in between the outlet of the De-I device and the Inlet of the pump. Worked great. Did quite a bit of washing of the driveway today. It's ugly but it works.
Hope to wash the car tomorrow but have to get the son's car out of the way first.