anyone try that thing with untreated {well} water? im curious if itll filter out the heavy mineral content... i just bought a house (finally) and it was recently converted to public utilities, however, i still have a functional well. If i can use it for car washing itll keep my water bill down.. i was thinking of building an activated charcole filter out of 2 inch pvc, but if this will work, its a much easier option.. unfiltered well water leaves nasty mineral stains which ofcourse one wants to aviod...