Reverse Osmosis systems

[DavidCampen]

Has anyone here constructed their own RO system? What sort of waste to product water ratio are you using?

I have found this web site to be a good reference:
http://www.spectrapure.com/

For most simple home systems it seems that a waste to product ratio of about 3:1 or 4:1 is being used. I plan to design and construct my own RO system and I am hoping to get the waste to product ratio closer to 1:1 without untoward membrane fouling. I will use 2 membranes in series so that I can get a higher axial flow rate along the membranes so as to flush the scale and if necessary I may inject CO2 or citric acid as an antiscalant.