[darbh]

Hi. I totally understand. I live in So Cal, also. Here's the data I have on the various matters touched on in this thread. I will present randomly.

The Problem. Is that the water has minerals in it, so, when the water evaporates, the minerals are left.

Filtration Systems: Most of these filter out particulates - little pieces of stuff -- through a mechanical type filter. Most minerals are completely dissolved, so they pass right through a particulate-type filter.

There are filters that target specific contaminants, but we are looking to avoid all minerals that would leave a visible or damaging residue, not just, let's say, reducing the amount of iron to safe levels for drinking.

Water Softeners. I believe that water softeners themselves do not remove minerals (or, if they do, they do not remove much). They alter the mineral balance of the water (replacing calcium, which make the water hard, with another substance, I believe). The benefit is that soap and detergents work better, etc., when the calcium is gone, but the water still has minerals in it.

Distilled Water. Has no minerals. It would be great to have a large tank of distilled water to use. We would not have any of these problems. It would also be very expensive to rinse your car with distilled water (and, lets not even discuss the cost -- or appearance -- of installing a large tank in the back yard!). I use it in spray bottles for cleaning windows, the car paint (in certain instances), wiping down the interior, etc. but not for rinsing.

Reverse Osmosis Device (makes "purified" water). Produces water that is nearly free of minerals. Cheaper than distilled water. Typically found under the kitchen sink, and used for drinking water. Note, however, that some cities rely on sea water than has done through desalinization plants that use this technology. I don't know anyone who uses this tech in the home for anything other than drinking water, but I am certain that some people do.

I am not that familiar with deionization (where the water is run through resin beds) and how good the deionized water is. I think this is what certain car washes claim produces "spot free rinsing." I doubt a device on the end of a hose would give such a result, but I do not know 100%.

Solutions. Rather than installing a reverse osmosis device and holding tank for the purified water, spots can be avoided by washing the car when the water will not evaporate before you can dry the car. In So Cal, this means the early morning or early evening or washing and drying in a protected space. I used to go the early morning route. But, if I was slow, or it turned out the day was going to be very hot, sometimes the day heated up faster than I thought it would. If I can, I now try to start washing around 7 PM. Its pretty cool AND its only going to get cooler. I make sure to keep "watering" the car as I wash it and after I finish washing the last panel, I water the whole car again. Then, I immediately begin drying, using a Toro Pro leaf blower (use a quick wipe of a towel to get the few, remaining small drops). So, the car was completely wet to begin with, then I rapidly blew the water off it, before it could dry. No spots.

[Edited by darbh on 08-16-2001 at 12:26 PM]