About that white material:
I did something a little different a while ago. I ran the system with distilled water intending to add WW later once it was leak tested. Well school started and I put it off. After about 2.5 months I finally added it.
The instant the WW hit my res it turned BRIGHT white. In a second or two my entire loop turned to milk
Gradually it settled out and coated my tubes over the next month or so. I applied acid to it, but was unable to remove it from my tube.
My guess is its a reaction between something dissolved in the water and WW.