Use it only to do a finish rinse, if not that filter will last you about 3-4 washes. Wash/rinse with regular water, then rinse the hard water off with the DI water. I made my own
DIC-20 and I order the refills from them, they last me about 4-6 months using them to rinse the car off. The DIC 20 is good for 300 gallons of DI water @ 0 ppm. That one is smaller than the DIC-10, which is good for 150 gallons @ 0 ppm, so a guesstimate would be around 75-100 gallons. Both DIC-20 and DIC-10 should be restricted to 2.5 gpm.
.75 gpm is the max flow for that filter, anything higher and you are not running at 0 ppm.
@Nineeightyone if you are a little handy at gluing together PVC pipe you can build one for around that price that would use a larger dual media filter. Don't know if the link below have both canisters, mounting bracket, and wrench included, but there are quite a few places online where you can get a set up like that at a similar price. 2 big blue filter housing (the 20")
https://123waterfilter.com/products...MORGmjQhUSOyeL5O5a8Cgk-xtGLCbFxcZGw94fVqQw2X0
You will need
this, and 2 of
this will be good to have, sucks that they are printing them now, I paid the same price for the original stainless steel rings. After that all you will need are the end fittings, depending on the housing you get they would be 1" mpt to 3/4 mgh.