What's new
By:
Car Wash Forum

This is a sample guest message. Register a free account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!

City just told me I can't use salt in my softener. Options?

2Biz said:
How do you run a SFR system without a softener if you have hard water?
Click to expand...
Buckeye hydro can comment, But IIRC I've seen RO specs that call for hardness below 10 grains. The purclean RO units had a removable, cleanable element that was supposed to prevent premature fouling and didn't spec soft feedwater.

I know I've produced RO water when my softener is not working before and I'm usually at about 8 grains of hardness with no perceived complications. As expensive as salt is getting for me it might be worth looking further into. It might be cheaper to replace membranes from premature fouling than continue paying $100/month for salt. One of my carwashes was actually initially set up to mix chemicals with RO water by the original owner, it wouldn't be hard to switch back
 
Commercial RO units typically are configured to operate at about 50% (or higher) recovery, meaning that 50% of the feedwater delivered to the system is recovered as permeate (purified RO water). Contrast that with residential RO systems which typically operate at only ~20% recovery. How do commercial systems operate at such higher recoveries? Is it better membrane technology? Nope. Better system components? Nope.

The answer is in better pretreatment. If you read the fine print re any commercial RO system, it will specify "0 Hardness" feedwater. With the hardness gone, there is nothing left to come out of solution as scale inside the membrane.

Can you run a high recovery RO unit with hard water? Sure you can. Should you? Absolutely not. If you do you'll significantly reduce the useable lifespan of those expensive membranes. You can plug a membrane with scale in as little as a day to a week - depending upon how bad your feedwater quality is.

Greg referenced a high recovery RO system that does not use a softener, but instead the vendor describes a "water stabilizer." These units don't remove hardness, but instead use a media that alters the hardness molecules such that they don't come out of solution (via a process called Template Assisted Crystallization). To my knowledge there have been varying results using this approach as RO pretreatment. The other downside is that the service life of the media is short - 1 to 3 years, and the media is incredibly expensive. In practice, any cost savings depend on a long service life, which is absolutely not guaranteed.

We recently did a large commercial job where part of the building received water treated with this media, but where preventing scale was critical (the boiler feedwater), the engineers specified a conventional water softener. I'm inclined to stick with softeners as RO pretreatment as well.

In an instance like the OP'ers, where a softener isn't an option, we just may spec this Template Assisted Crystallization media.

Russ
 
Last edited:
Greg Pack said:
The purclean RO units had a removable, cleanable element that was supposed to prevent premature fouling and didn't spec soft feedwater.
As expensive as salt is getting for me it might be worth looking further into.
Click to expand...

I do know that I am going to install residential wise a 3M AquaPure in line device that has a pretreatment (chemical mix gradually being released) cartridge that needs to be replaced every 4-6 months for a tankless to prevent calcification. A fellow laundromat owner said the 3M cartridges worked out for his DHW multiple tankless stage fired setup etc. How that could possibly help an RO membrane ... I have no idea. It could make the membrane possibly fail even sooner for all I know ... it would be nice if someone had actually tested this in a car wash situation.

With the tankless supposedly I have plan B that involves doing a calcium removal with vinegar every 6 months &/or installing a traditional water softener with salt (Plan C) etc.

BTW ... each 3M cartridge replacement cost is $33 each Walmart online free shipping.
 
Last edited:
2Biz said:
How do you run a SFR system without a softener if you have hard water?
Click to expand...
My guess is his water quality to to begin with must not be too bad, but I know he is not softening prior to the sfr. I’m not saying this would be recommended or the best thing to do, but he is making it work.
 
I'm glad I don’t have a water softener system to deal with. In our area we don’t have water softeners or water treatment systems. I wonder if the city is going to send out the water police to check and make sure he’s in compliance with the ordinance that’s been on the books since 1993. What do you have to do to convert your current system over to use potassium?
 
Randy said:
I'm glad I don’t have a water softener system to deal with. In our area we don’t have water softeners or water treatment systems. I wonder if the city is going to send out the water police to check and make sure he’s in compliance with the ordinance that’s been on the books since 1993. What do you have to do to convert your current system over to use potassium?
Click to expand...
Can someone elaborate on how potassium could help in some way??? Maybe...3M's secret ingredient is injecting a precise minute amount of potassium instead of the major process that regenerating does with traditional softening?
 
Last edited:
Buckeye Hydro said:
Commercial RO units typically are configured to operate at about 50% (or higher) recovery, meaning that 50% of the feedwater delivered to the system is recovered as permeate (purified RO water). Contrast that with residential RO systems which typically operate at only ~20% recovery. How do commercial systems operate at such higher recoveries? Is it better membrane technology? Nope. Better system components? Nope.

The answer is in better pretreatment. If you read the fine print re any commercial RO system, it will specify "0 Hardness" feedwater. With the hardness gone, there is nothing left to come out of solution as scale inside the membrane.

Can you run a high recovery RO unit with hard water? Sure you can. Should you? Absolutely not. If you do you'll significantly reduce the useable lifespan of those expensive membranes. You can plug a membrane with scale in as little as a day to a week - depending upon how bad your feedwater quality is.

Greg referenced a high recovery RO system that does not use a softener, but instead the vendor describes a "water stabilizer." These units don't remove hardness, but instead use a media that alters the hardness molecules such that they don't come out of solution (via a process called Template Assisted Crystallization). To my knowledge there have been varying results using this approach as RO pretreatment. The other downside is that the service life of the media is short - 1 to 3 years, and the media is incredibly expensive. In practice, any cost savings depend on a long service life, which is absolutely not guaranteed.

We recently did a large commercial job where part of the building received water treated with this media, but where preventing scale was critical (the boiler feedwater), the engineers specified a conventional water softener. I'm inclined to stick with softeners as RO pretreatment as well.

In an instance like the OP'ers, where a softener isn't an option, we just may spec this Template Assisted Crystallization media.

Russ
Click to expand...

My point exactly! Feeding an RO System with anything other than typical softened water will cost cost you no matter how you do it! I read where you use a lot more Potassium to soften water v/s using salt in comparrison. And like the PO explained, the cost per bag of Potassium is $36, about 6x higher than using salt. Even more than 6x when you factor you have to use more Potassium to achieve the same hardness as using salt. This is not a good position to be in.

I run zero grain softened water to my RO system. The filter is going on 12 years old and still produces below 5ppm water....This aligns with what Buckeye mentions above...
 
You must log in or register to reply here.
Back
Top