Deionized (DI) Water

[The Critic]

My driveway faces South. During the spring and summer months, it is nearly impossible to wash any cars during daylight hours without spotting. I usually have to do my washing before 7am or after 8pm.

I am considering a DI water system and want to utilize it as follows:
- Mix soap solution using DI water.
- Pre-rinse vehicle with tap water, but perform a light rinse with DI water before washing with soap. This way, if water dries while the vehicle is being washed, there is no spotting.
- Rinse off soap using tap water, but perform a final rinse using DI water.

With those above steps, I think I can limit DI water usage to under 15 gals per wash.

Does anyone have recommendations for a DI system? I think this system provides the lowest cost per gal:

https://dirinse.com/product/d-i-rin...MI0OuL1qSMiAMVYh6tBh3mwjl1EAQYASABEgKS_fD_BwE

 

[Rand]

I use R/O water as final rinse. seems to keep almost all the water spots away.
I also use it in the wash bucket and any chemicals you dilute.

 

[skyactiv]

Before anyone suggests one, I thought I'd be smart and bought a RV water filter thinking I could wash my car and skip the drying step. It didn't help.

 

[doitmyself]

DI systems are somewhat simple and universal: a tank, a top cap/distribution tube, and the resin. Your model has a very convenient bypass valve. Cheaper systems can be had without the valve if you can live with the inconvenience of switching hoses. The quality of these three components might vary, i.e. Chinese made vs. U.S. made. My point: in general, a one cubic ft. model of any "decent" brand should produce about the same amount of DI water.

The mixed 50/50 resin tends to run around $230 +/- per cu. ft. and there might be some lesser quality products being pushed if you are not careful. Figure the resin cost replacement into your calculations moving forward.

Your link's claim of 4,000 gallons capacity from their one cubic ft. model at 110 TDS raises a red flag. TDS is a less accurate measurement method vs. conductivity. The capacity of the linked/any unit will vary greatly based on the quality of the incoming water. Their claim seems optimistic to me. I.E., this resin company claims that 100 TDS water supply will result in only 3200 gallons of DI water: https://xeroproducts.com/products/x...MI8u2r1O2TiAMVHkn_AR1jrh2iEAQYCCABEgJdAfD_BwE

"Maybe" the difference is because car wash water quality can be allowed to dip a bit higher in TDS before spotting occurs?? My point is that your cost per gallon calculations/comparisons might not be correct without doing some water testing, etc.. Too many variables.

Finally, look into the cost of renting DI tanks from a local water conditioning company (Culligan, etc.) and compare the cost of ownership. I only have costs for a commercial dual tank greenhouse system.

Here's a few link's if you care to OCD on this:
https://tuckerusa.com/blogs/news/th...MI8u2r1O2TiAMVHkn_AR1jrh2iEAAYAiAAEgJ0OPD_BwE (window cleaning companies use DI)

https://www.omniapartners.com/suppl...ndustrial_Water/Assets/di-tank-user-guide.pdf (OCD industrial info)

Oh, yea, your system looks as good as any. And, it is based in California?, more local to you.

 

[JHZR2]

No recommendations, but this was the premise of the Mr. Clean car wash system sold about 15 years ago.

You may be better off getting a folding 10x10 tent and using that. It will be more useful.

 

[CleverUserName]

I’ve washed my cars at work which has a well and very hard water.

After washing I rinse with a dilute white vinegar solution in a Hudson sprayer then towel dry. It removes hard water spots from chrome and glass as well.

 

[The Critic]

Your link's claim of 4,000 gallons capacity from their one cubic ft. model at 110 TDS raises a red flag. TDS is a less accurate measurement method vs. conductivity. The capacity of the linked/any unit will vary greatly based on the quality of the incoming water. Their claim seems optimistic to me. I.E., this resin company claims that 100 TDS water supply will result in only 3200 gallons of DI water: https://xeroproducts.com/products/x...MI8u2r1O2TiAMVHkn_AR1jrh2iEAQYCCABEgJdAfD_BwE

"Maybe" the difference is because car wash water quality can be allowed to dip a bit higher in TDS before spotting occurs?? My point is that your cost per gallon calculations/comparisons might not be correct without doing some water testing, etc.. Too many variables.

Good find, thanks. The Xero unit is quite a bit cheaper, but having a bypass valve is critical to my planned workflow. I'll have to research if a bypass valve exists for the Xero units.

I have a TDS tester coming tomorrow -- will need to do some testing.

Finally, look into the cost of renting DI tanks from a local water conditioning company (Culligan, etc.) and compare the cost of ownership. I only have costs for a commercial dual tank greenhouse system.

I was unable to find anyone local.

You may be better off getting a folding 10x10 tent and using that. It will be more useful.

I don't have any room for storage. Also, efficiency is important to me these days -- having a job take 45 min vs. 55 min is often the difference being able to do it, or not at all.

After washing I rinse with a dilute white vinegar solution in a Hudson sprayer then towel dry. It removes hard water spots from chrome and glass as well.

The vinegar is a mild acid, so you're just removing any water spots during the drying cycle. I'd prefer to prevent the water spots, if at all possible.

 

[shortyb]

I was going to second the EZ-UP type of temporary cover until you mentioned storage. I used one plenty of times when I couldn't get shade for a wash or mechanical work that needed to be done outside. Fortunately our county water service has insanely low TDS which still amazes me. Our water is sourced from nearby mountain runoff in a manmade lake. Very little if any spotting.

What about a wax-as-you-dry product? Used a Meguirs one on the black cruiser and never spotted, even in direct sunlight.

 

[JHZR2]

I don't have any room for storage. Also, efficiency is important to me these days -- having a job take 45 min vs. 55 min is often the difference being able to do it, or not at all.

I hear you on the 45 vs 55 minute thing. It is so true!

A good DI system will still take wall space and piping. I bet in the end a folded tent will be about the same, and you’ll want one for kids activities anyway if things like outdoor swim team, soccer, etc become important. Just sayin’ from experience

 

[Pablo]

I am curious about this, because I think DI systems are not that perfect. Both DI and RO water leave some deposits when boiled away in a clean stainless pan. And is that ring some salts/minerals or magic car coating (or something left in the pan)?

 

[SHOZ]

I am curious about this, because I think DI systems are not that perfect. Both DI and RO water leave some deposits when boiled away in a clean stainless pan. And is that ring some salts/minerals or magic car coating (or something left in the pan)?

RO is a filtering membrane system and DI is a acid/alkali mineral stripper.

RO should be quite low in TDS <5ppm. DI, if it isn't a chemically polar mineral it will not take it out.

 

[Pablo]

RO is a filtering membrane system and DI is a acid/alkali mineral stripper.

RO should be quite low in TDS <5ppm. DI, if it isn't a chemically polar mineral it will not take it out.

Yes, and why are the deposits there. Or better, what ARE the deposits?

Try it with distilled water.

 

[SHOZ]

The DI we used at worked used hydrochloric acid and sodium hydroxide to strip the minerals. But both will leave behind deposits as you will never get a complete rinse. Even 5ppm will leave deposits as other wise it would be 0ppm. Distilled water should be close but when it is first condenses there is always a slight contamination 100% pure water is very corrosive.

 

[srfdude]

Not sure what your water hardness is, but in CA it runs between 250-350 ppm. I think 110 ppm per the ad is unrealistic; it will cut the lifespan down considerably. I use PureWater household filters, and love them. LIfespan is always shorter than they advertise, but hey, thats life.

 

[JHZR2]

I am curious about this, because I think DI systems are not that perfect. Both DI and RO water leave some deposits when boiled away in a clean stainless pan. And is that ring some salts/minerals or magic car coating (or something left in the pan)?

There’s different levels as I understand. There’s really pure DI for chemistry labs, reactors, high voltage electronics, etc., and then there are grades that have some higher level of pass-through.

IIRC, true DI will show no conductivity, but it will start to absorb CO2 from the atmosphere and begin to show conductivity in time.

 

[JHZR2]

Yes, and why are the deposits there. Or better, what ARE the deposits?

Try it with distilled water.

Because RO is not perfect. By a long shot. You’re balancing flux and pressure (energy use) with cleanliness.

 

[SHOZ]

If the DI has a resin bed it will foul over time..

 

[Rand]

Because RO is not perfect. By a long shot. You’re balancing flux and pressure (energy use) with cleanliness.

Neither is DI.
but this is a car wash.. not industrial applications.

I have R/O system and I love it for drinking water.. the city water here is not great.
removing 90%-97% is sufficient.. and I drink 4-5 glasses a day.

Since I have it, I use it for the car wash everything except the rinse.. and after the rinse I pour a gal or 2 on and then dry with battery leaf blower then towel.
Works better than house water.

I'm not sure this 650$ system with expensive resin will be any better.

AFAIK, DI resin will be reducing the conductivity I would at least use a whole house sediment filter before it if not sediment/ carbon filters.
But maybe I am missing something as I've never used one of these portable type systems just seen them in action on industrial machines.

Also what is the resin system.. is it canister exchange? if there is no local place that can be pricy.
I've seen both the kind where you pack it manually and the contained systems (much nicer)

 

[JTK]

C'mon man.. For your daily drivers? I hear you though. In the summer I try to park somewhere in the shade on my front lawn when washing the cars.

You're going to have spots on the finish and glass the next day anyway.

I know what we go through at work with our RO, DI and carbon beds for our steam systems. I wouldn't bother for my daily drivers, but I could give yours a quick bath if you swing by the plant in the off hours! LOL

 

[burbguy82]

I have a story about DI water.........

Years ago, at a chemical plant in SC called Atotech, I did an upfit in their testing lab. Atotech makes chemicals for the auto industry......

One of the systems they have on site is a DI water distribution system, and it was in my scope to make some changes and additions to the existing system, to make a long story short.

In the specs for the job, in simple terms it called for Sch80 PVC for the pressure lines, and minimum solid core SCH40 for the drain lines, and specifically stated "no metal" for any piping within the DI system......hmmmm I wondered.

So at the finish of the job, there were some special drains for the sinks, from which the factory manager was supposed to provide, that were not yet delivered....and we needed to get an inspection by the county, for final payment. So I got me several metal drains to put in place as a temporary part, to get past inspection. (construction industry politics). I told the plant manager this plan, and they agreed that it would likely work "OK" for a week or so, but as soon as the drains came in, I needed to be onsite to install them.....he said the drains would probably be in "bad shape" by then

Of course, I know nothing of DI water and its effects, so I had no idea what was in store.

When the new drains came in, I went to install them right quick.........and WOW.

The metal drains that I had installed in the sinks were nearly gone. The drains had been so greatly eaten away by the DI water, that when I went to remove them, they crumbled.

The plant manager, said to me "thats about what I was expecting".

He explained that DI water is very much like an acid to metal. "God intended water to have stuff in it, like minerals and such"

In later investigation, I found out that DI and RO faucets, were 100% plastic inside.


In conclusion, washing a car in this kind of water is not a good idea.