Its about to get extremely hot again here in Texas and I always have trouble washing and drying the cars quick enough before they dry with spots (and I typically wash two or three cars each weekend). I've recently been trying this process recommended to me by a mobile detailer where I wash, rinse and dry one or two panels at a time, then carefully try to avoid getting any droplets on the cleaned panel(s) but that takes much longer. Have been researching DI spotless rinse systems but the internet is so full of conflicting claims its hard to know what I would be happy with. Consumer level systems seem to be offered from $150 to $600. There's so many different styles, mixed-bed resin (with varying ratios or no published ratio) vs separate cation and anion resins, bags of resins vs cartridges, one, two and three stages of filtration or just one big cylinder, built-in bypass or just quick disconnect the hose. Some even recommend a carbon pre-filter and I read one vendor that actually said it was counter-productive.

Seems like all the video reviews seem to do is measure how many gallons they got out of it before the resin went bad and I'm sure my results would be much different anyway. They all seem to work just fine in the reviews, but the only difference will be how many gallons you get out of it before changing the resin/cartridge which depends on the source water. Sure it'd be nice if it didn't cost a fortune, but really I just want to make the car wash a less frustrating process and maybe save me a little time. Just changing cartridges sounds easier, but seems like every time I buy something like that whether its a battery or a vacuum filter, it's not long before I can't buy the proprietary refills anymore. So I ask fellow members of this obsessive-compulsive cleanliness support group, what DI rinse system are you using and just simply how do you like it.

 

I cannot speak to any of the DI cleanliness systems as I simply have not looked at them. But, where I can help is in understanding them. My job requires me to know the difference between types of water (distilled vs spring vs tap vs salt) and what the affects are with each on various systems. What I will say is that using only a charcoal bed or something of the like is not going to do what you are after. You are definitely after a resin bed. NOw, whether it is a mixed bed or separate cation and anion bed, I do not think that will make much of a difference unless you know that your local water is high in some impurity with almost none in anything else. This would benefit you in the fact that you would then most likely only need to replace either the cation or the anion bed. You go with the mixed bed, you are going to end up replacing the whole thing anyways. As for how pure you need to get the water, honestly, I think if you can get it down to 2-3 ppm total dissolved particulate, you are going to be good. You do not need a system that can take it down to 0.5 ppm or less. As for figuring that out, I would tell you to keep things simple and simply get a Brita water pitcher (the one that comes with the water probe in it) and use that to get an idea of what levels you are dealing with. Fill a clean bucket and use the probe to see what it says.

The other thing that I would tell you to consider is either washing underneath a 12x12 canopy that you then move from one end of the car to the other or washing the car at home and then do a final spray at say a car wash where you are under cover and in the shade which will give you more time to wipe the car and get rid of the water spots.

 

Thermo, you wouldn't happen to know enough chemistry to decipher the City of Fort Worth Drinking Water Quality Report would you? Theoretically and according to some youtubers and web sites, anion gets used up much faster than cation and so having them in separate canisters can supposedly save money replacing the cation resin about one third as often as the anion. Also, I read that most of the mixed bed resins are 50/50, but that supposedly there is a vendor somewhere that sells like a 30/70 mix but I haven't found it. The City's water quality report lists parts per billion of all sorts of nasty things still left in the water after treatment but I don't know which of them would be removed by cation vs which would be removed by anion (or which are more or less responsible for water spots on my car). According to multiple tests of my Amazon TDS meter, the water at my house is running anywhere from 80 to 115ppm this week but the City's published lab report from 2023 (I guess 2024 isn't out yet) shows a range of 184 to 274. And I don't think they've made any major upgrades to the treatment plant or changed sources in the last year. Probably these little electrical probe meters just aren't very accurate.

 

pdupler, I think I can help with this some. This is where I am going to recommend you get yourself a table that lists all the elements (periodic table). If you draw a line down the middle of the table (top to bottom), the items to the left of the line tend to loose their electrons and therefore will be removed by the anion resin bed. These items tend to make what are referred to as acids (HCl-hydrochloric acid, sulfuric acid (H2SO4, etc). A lot of your organics and whatnot will be removed by the cation resin. You will also see where it will remove bases. You may also find that you want to get what is call an H-OH resin bed. THis works on both acidic and basic items as most of the things in the water break down to an item that is positively charged (which will get replaced by the H side of the resin) and the other half of that compound will have a negative charge to it and be replaced by the OH side of the bed. THe H-OH resin beds may be a little more expensive, but they are not affected by having a lot of acid or a lot of base run through it.

As for leaving stuff behind, I think about any resin bed you get is going to do what you are after. I would say to start wtih a fairly cheap one and if you are not happy with that, then you can start upgrading things at that point.