CR Spotless or other DI water systems

[Auggie]

2. Regenerating mixed bed resin using lye and hydrochloric acid is difficult, expensive and not cost-effective

I realize this thread is a year old, but I'm curious as to what were your regeneration costs that leads you to claim that regenerating mixed bed resin is "expensive and not cost-effective?"

I've thoroughly read the entire original How to recharge DI resin thread posted on an aquarium forum, and it takes approximately 6 ounces of Lye and 12 fluid ounces of hydrochloric acid to regenerate a typical media chamber of a Pentek Big Blue-style 20" x 4.5" canister that the larger CR Spotless system uses, which averages 8.5 pounds of mixed bed resin per canister. You also need at least 36 fluid ounces of RO/DI water for dilution and two gallons for rinsing.

A 3-pack of Rooto 1030 1b Drain Cleaner (100% Lye) costs $25.49 at Walmart ($0.53/ounce), and 1 gallon of Klean-Strip Green Muriatic Acid costs $9.98 at Home Depot ($0.16/ounce). For RO/DI water, unless you have a drinking water or aquarium RO system, you should be able to get this from local aquarium shops so prices can vary widely, but shouldn't be too expensive.

This equates to 6oz x $0.53/oz = $3.18 of Lye and 12oz x $0.16/oz = $1.92 of hydrochloric acid to regenerate one Big Blue 20" canister of resin, or $5.10 total.

The cheapest bag of mixed bed resin I found was $185 for 1 cubic foot (~45 pounds) shipped, or $34.94 per Big Blue 20" canister. If you subscribe to the OP's third bullet point that "There are no 'cheap' sources of mixed bed resin," then you probably would purchase the uber expensive CR Spotless replacement resin at $60 per Big Blue 20" canister.

Thus from the linked pricing above (as of May 2020), it costs $5-7 (depending upon RO water source) to regenerate one canister versus $35-$60 to replace one canister of mixed bed resin; ergo, it's much less expensive and extremely cost-effective to regenerate versus replace.

Certainly, it's more tediuous, and more dangerous to regenerate due to handling caustic chemicals; this alone could be the driving factor for many people to opt for replacing versus renewing.

But I just wanted to dispel this notion that regenerating resin is expensive, at least for those of us in the US.

[Route246]

I realize this thread is a year old, but I'm curious as to what were your regeneration costs that leads you to claim that regenerating mixed bed resin is "expensive and not cost-effective?"

I've thoroughly read the entire original How to recharge DI resin thread posted on an aquarium forum, and it takes approximately 6 ounces of Lye and 12 fluid ounces of hydrochloric acid to regenerate a typical media chamber of a Pentek Big Blue-style 20" x 4.5" canister that the larger CR Spotless system uses, which averages 8.5 pounds of mixed bed resin per canister. You also need at least 36 fluid ounces of RO/DI water for dilution and two gallons for rinsing.

A 3-pack of Rooto 1030 1b Drain Cleaner (100% Lye) costs $25.49 at Walmart ($0.53/ounce), and 1 gallon of Klean-Strip Green Muriatic Acid costs $9.98 at Home Depot ($0.16/ounce). For RO/DI water, unless you have a drinking water or aquarium RO system, you should be able to get this from local aquarium shops so prices can vary widely, but shouldn't be too expensive.

This equates to 6oz x $0.53/oz = $3.18 of Lye and 12oz x $0.16/oz = $1.92 of hydrochloric acid to regenerate one Big Blue 20" canister of resin, or $5.10 total.

The cheapest bag of mixed bed resin I found was $185 for 1 cubic foot (~45 pounds) shipped, or $34.94 per Big Blue 20" canister. If you subscribe to the OP's third bullet point that "There are no 'cheap' sources of mixed bed resin," then you probably would purchase the uber expensive CR Spotless replacement resin at $60 per Big Blue 20" canister.

Thus from the linked pricing above (as of May 2020), it costs $5-7 (depending upon RO water source) to regenerate one canister versus $35-$60 to replace one canister of mixed bed resin; ergo, it's much less expensive and extremely cost-effective to regenerate versus replace.

Certainly, it's more tedious, and more dangerous to regenerate due to handling caustic chemicals; this alone could be the driving factor for many people to opt for replacing versus renewing.

But I just wanted to dispel this notion that regenerating resin is expensive, at least for those of us in the US.

The ingredients were inexpensive but I have a lot of resin so the price escalates quickly, especially for lye. A cubic foot of resin costs about $200 shipped in my experience and that is at the low end and it is China-sourced.

Continuing, I have a lot of resin for a batch (about 1/2 cu ft) so it needs to be done in multiple batches. You do not recover 100% as some is lost in the separation process. You also do not get 100% capacity from regenerated resin so you lose a little in that process.

I bought restaurant-quality vessels to do the processing. The separation is the most difficult. These are all very caustic and dangerous products to work with so I used some personal protective gear in the process (pre-COVID). Goggles, smock, gloves, mask, etc. but these are not necessary, just prudent when working with products that can blind you, burn you and poison you if you're not careful. I'm OK with that part but it is not free to do it in a safe manner.

I watched many youtube videos on doing this and most of them were small-scale, much smaller than my requirement using inverted 2-liter soda bottles, etc. I needed bigger scale vessels and those were on the order of $30-$40 from the local restaurant supply. I also needed a colander, sheer cloth, funnel intermediate storage vessels during processing.

The biggest hassle is the separation. I figure I lost 15% when doing the separation at my scale (not 2-liter bottle youtube scale). I used a ladle and large industrial-grade baster for this. Even so, the separation was not perfect.

I also take great exception to the amount of water required. The rinsing required during and just after separation is not an easy process, either at my scale. The youtube videos are very misleading. It takes a great deal of DI water to rinse so that the pH level approaches neutral.

BTW, I abandoned the idea to use "tap water" fed into my resin now and I also abandoned having real-time generation of spot-free water. This was huge for me. I use a 50-gallon barrel to store DI water now with a pump to garden hose. The barrel was $15 on Craigslist and the pump varies based on type and source but is under $100 in most cases. I bought parts for making my own RO (reverse osmosis) water which brings TDI from about 450 down to 10 or 15 but only generates slowly like 10 gal/hour. I then pump that 10-15-TDI water through the mixed bed resin and it yields 0-TDI water (close to distilled water TDI). This gets stored in the 50-gal barrel. TDI meter shows 0. At this TDI input level the mixed bed resin will last a very long time, much longer than feeding it 450-TDI which basically lasts a few hundred gallons at best and still yields 10-15-TDI out.

The key piece to the puzzle is the membrane. Search "reverse osmosis membrane" to get a look at the cartridges. There are a few key pieces to plumb together but it can be done easily as long as you have all the parts. The waste water (which is substantial) flows into our garden so none of that is wasted, either.

I guess "expensive" is relative but my time is worth something. I'd rather be working on the cars more than regenerating resin to be perfectly honest. It is a huge time commitment to do the regeneration.

[Route246]

One more thing, the 15% loss in separation was not really "loss" it was more like resin that did not separate cleanly so it is neither and did not get processed with the acid or lye separately. It just goes back into the mixed bed as is.

Ideally, I would have preferred to be able to regen in-line, pumping first acid through and then pumping lye through but this doesn't work that way. Had it worked that way then regeneration (like soft water regeneration with salt or potassium) would have been trivial. Separating it is a royal PITA in my opinion.

[Auggie]

In the aquarium link I posted, the OP went to Big Blue size and to handle that, he switched to an inverted 5 gallon water jug (with 1/2" bulkhead fitting, 1/2" ball valve, and 1/2" to barbed fitting to slow the drainage) for the separation portion, cradled in a 1" square tube frame 36" high to allow for a buckets to slide underneath and it all worked out for him.

I will say that none of the posts on that thread indicated the severe loss of resin that you are experiencing, nor have they lost the amount of deionization capacity that you are experiencing (the OP eventually added a step to bath the anion in the used acid after separation and first rinse to get full "recharge," followed by a second rinse), though it appears you truly went "big" in your regeneration setup in order to do much larger batches, and popped for industrial grade vessels. There have been posts in the thread where they didn't get the separation of the anions/cations as expected, but the recommendation was either to reduce the batch (too much resin in the container size being used and/or for anion/cations to properly separate under that much mass) and/or to adjust the lye dilution ratio. FYI, there were several posts from industrial water professionals that did regen on a enormous scale, but they used separate beds and fed chemicals and rinse under pressure through those beds so nothing had to be removed or separated.

Speaking of large volume, since you're processing larger batches you need higher volumes of RO/DI water for rinsing. In addition, the overall expenditure in chemicals will of course be higher, but cost per pound should remain constant, if not lower since you should be buying in larger bulk. And so too will the overall cost of purchasing an equivalent large quantity of NEW resin be higher, but again, the price per pound should remain constant; ergo, regeneration will monetarily always be significantly less than replacement.

The OP in the aquarium thread has been doing the ratio's specified for at least 10 years so I'd expect his experience would be more applicable for me as my setup (5 gal jug) will be similar.

For my own piece of mind, I'll be wearing full PPE myself: face shield ($35), chemical-resistant apron ($20/pair), and sleeve-length chemical-resistant gloves ($15).

Eventually I will be switching to a full RO/DI setup similar to what you are now using as that would allow the DI resin to stretch out longer due to low flow which allows longer, more efficient contact time, but that's for another day when I get a saltwater aquarum running. For that setup, I plan on using a 275 Gal IBC Tote for storage.

Regardless, I would still be regenerating my resin in that system, but I will have a dual-bed DI setup (two canisters: one anion, the other cation), followed by mixed bed (third canister) for "polishing." This will allow me to regen the dual-bed canisters separately the way you mentioned wanting to do it. From reports on aquarium forums, the third mixed-bed canister gets depleted very, very slowly and would rarely need to get regen'd/replaced.

With all that said, I agree that regeneration takes time and labor, so each person needs to evaluate what their "time" is worth and decide if regeneration makes sense in that context, in addition to the hazards involved with regen.

I do appreciate sharing your get-up as it puts everything in perspective while provide some nuggets of wisdom and techniques...

[Markymapo]

Spx6001c Sunjoe self contained battery operated and 1 gallon distilled water ($1) for the final rinse ( the F150 uses 2 gallons for rinsing), roll out of garage roll back in. Works great for a weekend warrior with only 4 vehicles to wash biweekly.

[ERP]

I picked up an 8,000 grain portable water softener and haven’t gotten around to using it yet. I hadn’t realized they were such a hassle to regenerate.

[Bearcats98]

Spx6001c Sunjoe self contained battery operated and 1 gallon distilled water ($1) for the final rinse ( the F150 uses 2 gallons for rinsing), roll out of garage roll back in. Works great for a weekend warrior with only 4 vehicles to wash biweekly.

I never knew such a thing existed! This is perfect to get that last rinse in with no water spots!

[Azure]

I never knew such a thing existed! This is perfect to get that last rinse in with no water spots!

I thought about getting one, but they are super expensive for a basically mediocre pressure washer. The idea is awesome though!

[Bearcats98]

I thought about getting one, but they are super expensive for a basically mediocre pressure washer. The idea is awesome though!

Yeah, its $$$. But my time is worth money too. To be able to rinse it off...worry much less about water spots which means less touching the paint for correction. But I am pretty good at rationalizing things!

[Azure]

Yeah, its $$$. But my time is worth money too. To be able to rinse it off...worry much less about water spots which means less touching the paint for correction. But I am pretty good at rationalizing things!

Haha, I’m good at it too. My wife will tell you that lol.