Spot Free Rinse Systems

[2black1s]

I've struggled forever with water spots when washing my bikes and cars. The TDS (Total Dissolved Solids) level of the tap water at my home is in the 375-425 range. That equals a lot of water spots.

I couldn't dry my vehicles fast enough to eliminate spots, especially on my bikes. Even using a leaf blower on the bikes didn't do much good... It made smaller water spots but water spots nonetheless.

On my HD Ultra Limited I would spend literally a couple hours removing water spots after washing. And even then, there are so many nooks and crannies on that bike that it's impossible to remove every water spot.

Now! Since I'm such a glutten for punishment, I recently ordered a new Chevy Colorado Z71 and guess what color? Black. To go along with my two black Harley's. Ordering this new truck motivated me to look into spot-free rinse systems.

After much research and nearly buying the CR Spotless System, I opted to build my own system. I decided on a combination of RO (Reverse Osmosis) and DI (Deionization)... The RO to remove most of the TDS followed by a DI filter to complete the process. RO followed by DI is much more economical to operate than a straight DI system, thus my decision to go with that configuration.

Anyways, I tried the system out this weekend on three bikes and I'm extremely happy with the results. I used the system for only the final rinse, followed by a leaf blower on the first two bikes, and then for my Ultra Limited, which is the hardest of the three to clean, I simply rinsed and pushed it into my garage and let it dry overnight on it's own. Letting it dry on it's own is not something I plan to do regularly, but I wanted to try it here simply to assess the effectiveness of my new system and process. The results were amazing. The bike dried perfectly without a single water spot. The bike looks crisp and clean - everywhere - chrome, engine, paint... everything!

I'm still in the experimenting stage but happy so far. I'd like to modify the system to increase it's capacity to the point of using the "clean" water for the entire wash process rather than only the final rinse, as I've done so far. But even the way it is, it's a major improvement. And with a few process improvements as I get more experience using the system, this project was definitely worthwhile for me.

Now I just need to figure out how to add some photos...

[allenk4]

What is the math on RO/DI vs DI?

Please include the total cost of the water for the RO system

Thanks

[2black1s]

What is the math on RO/DI vs DI?

Please include the total cost of the water for the RO system

Thanks

DI = ~ $0.60 to $0.80 per gallon
RO/DI = ~ $0.26 per gallon.
I put this right up front for a quick reference. You can continue reading if you're interested in the calculations and the systems compared here. These are estimates only and based on an untreated TDS level of 400 ppm.

Discounting the initial cost of the system(s), which are in the same ballpark, the estimated operating costs are ...

Assuming a starting TDS of 400 (like mine) the estimated cost per gallon using the CR Spotless System is about 0.60 to 0.80. I determined that from data on the CR Spotless website. Their system produces ~300 gallons of product per resin/filter change @ 200 TDS input. At 400 TDS input that amount is cut in half to ~150 gallons. Filter/resin changes cost between $90.00 and $120.00. ($90 if you change the resin in your existing cartridge or $120 if you replace the entire pre-loaded cartridge). Doing the math results in a cost of $0.60 to $0.80 per gallon. You can also buy bulk resin to lower this cost somewhat, but it's still relatively expensive.

My home made system produces a gallon of water for ~$0.09 (RO only - not processed throught the DI filter). That is based on the pre-filters (sediment and carbon) specified life of 2,000 gallons (total) or ~500 gallons product and a cost replacement of $30.00. The RO Membrane should last for 8,000 gallons (total) or ~ 2,000 gallons product and a cost replacement of $60.00. Doing the math results in a cost of $0.09 per gallon. In addition, there is the cost of the water going down the drain with the RO system since it takes ~4 gallons to make 1 finished gallon. I'm not sure what that cost is but in the overall scope of things it's fairly insignificant.

Then add to this the cost of the final DI step. The DI filter I'm using has a capacity of 266 grains before needing replacement. Therefore, with the RO water (actual 20-30 ppm, averaged to 26.6 for the sake of simplicity in this equation and being equal to 1.55 grains per gallon) going into the DI filter, the DI filter can process 172 gallons before needing replacement at a cost of $30.00. Doing that math results in a cost of ~ $0.17 per gallon.

There are other systems out there, both DI, RO, or RO/DI, and their costs may vary - but for the two systems compared here the straight DI estimated costs are ~ $0.60 to $0.80 per gallon and the hybrid RO/DI estimated costs are ~ $0.26 per gallon.

Hope that addresses your question.

[SameGuy]

Could the "wasted" RO water not be captured and used for pretty much any other purpose (such as the wash steps)?

[2black1s]

Could the "wasted" RO water not be captured and used for pretty much any other purpose (such as the wash steps)?

You could... But I don't think you really want to. The TDS level of the "wasted" water is ~ 30% higher than the tap water you start with.

I'd use it to water my lawn but that's about it. And with the relatively small amount of water I'm making, the associated "wasted" water would hardly make a dent there.

Just not worth the effort to me.

[SameGuy]

I see your point.

Yeah, if I were very AR about water conservation I'd probably switch hobbies. But using the byproduct water for lawn/garden/etc. is exactly what greywater reuse is all about. Something to think about if you're in an area with heavy water restrictions, or are simply more concerned with water conservation.

[Bullitt 3309]

Can you post or pm me a build list please?

[2black1s]

Can you post or pm me a build list please?

PM Sent.

[Hoytman]

Can you post or pm me a build list please?

I would also like a build list.

Where did you buy everything from?

[SameGuy]

Yeah, may I also be included in the PM? I'm also curious about the sources and total costs. I probably won't get around to the build until late winter, but I'd like to start getting things together.