How to recharge DI resin

[yardboy]

Yardboy

If you have recharged for 10 years, that is long before I posted recharging instructions. The TWP instructions I listed on the first post are much older than this thread. Are you using these instructions, or do you use a different process? I am very interested how you recharge and the products you use to do the job.

27 years operating and overseeing the operation of water treatment plants producing ultrapure water, the latest with 150gpm RO and 60 cu. ft. mixed bed to produce 0.054 uS/cm- water quality. Your instructions were fine for small systems, only difference I do is 4% acid (40 gallons of 95% H2SO4) and 5% caustic (200 gallons of 25% NaOH) per regeneration. Same resins, same RO membranes, same operating principles(just more and bigger) I admire that you took the time to puzzle out how to do it on the small scale.
Sorry if it sounded misleading but was trying to get point across that resin can last a long time if properly pretreated (I have yet to see how long resin can last with an RO in front of it. Have never had to replace any since no particulate or organics get past the RO, barring a mechanical failure)
We regenerate the resin beds before silica exceeds 10 ppb (designed for 3.5 million gallons throughput between regens) and we regen about every 3 weeks and have been for years.
Since it's my newest project, quite proud of it,
The 150gpm RO with Dow Filmtec membranes (8" diameter, 48" long, 5/vessel) 2 pass with 75% recovery

Mixed bed with Rohm & Haas Amberjet resins. After exhaustion, bed is backflushed to seperate resins, regenerated in tank using blocking flow of water to keep acid/caustic off anion/cation resin

I regenerate my resin at home just as you suggest, very clever how you used motor oil valve to seperate resins, 2L coke bottles for regeneration beds, muriatic and lye for regenerants. I find no fault with it, though using purer sodium hydroxide would be better but very difficult to find for laymen.
Only problem is that it can be very dangerous, and many people shouldn't even attempt it. Hopefully they know who they are. As for me, I'll keep on doing it until I get out of reefkeeping, as it is one of the most important ways we can keep the water quality up in our tanks. If I used tap water, I would be adding 2 ppm phosphate to my tank, as the water here is corrosive and the phosphate is used to reduce the corrosion and prevent excessive levels of copper, lead and zinc in our drinking water.
Regenerating in this way is much cheaper than buying resin each time.

 

[dngspot]

Most impressive.

 

[Rhodes19]

Wow!!! Talking about going big. Thanks for sharing yardboy.

 

[yardboy]

I've consulted on problems that the local Gulf World had with their system. It was just a bit smaller, nearly identical looking. I've not seen it, but I can imagine how big the Atlanta Aquarium or the Aquarium of the America's in New Orleans (just to name a few local ones) would be!
I also have a 250 gpm system, that approaches it from a different direction. The RO is a two pass. While conventional industrial RO's have the waste pass through a second set of membranes to increase recovery rate, our larger one has a second array for the permeate so that it goes through a second set of membranes. It makes the quality of water much higher that way, and then we pass it through a very much smaller demineralizer that lasts quite a while (~2 million g) before regeneration. In the future I'm wondering if they will develop small scale electrodeionization (EDI)where the water to be purified passes across charged membranes which electrostatically attract the ions. We'd be using one here but they don't stand up so long term to high levels of calcium, which we have quite a load of, since Florida sits on top of a fossil coral reef, which the rain is slowly dissolving away. Florida, home of underwater caves and sinkholes!

 

[DeathWish302]

Does anyone think there may be a problem with mixing some standard color-changing resin to top off the MaxCap and Silicabuster cartridges I'm about to recharge? Has anyone recharged the MaxCap and Silicabuster cartridges and if so what is your experience? I was not happy when I found my Silicabuster (2nd DI Canister) was reading 1ppm after 700gal Spectrapure claims 1600gal with MaxCap changes after reaching 75%ppm of the post-membrane ppm. My RO has been flopping between 3-4ppm and the 1st DI (MaxCap) has been rock solid at 1ppm for over 5months. Suddenly I have 1ppm coming from 2nd canister. Not a happy camper, so I would like to try the recharge before I totally drop the MaxCap/Silicabuster methodology for the standard nuclear grade mixed bed bucket of resin I have awaiting recharge.

TIA

 

[dngspot]

I have not done this but it is worth giving it a try

 

[yardboy]

Deathwish,
It is unusual for a company to state # gallons throughput on resin when the quality of the feedwater is the determining factor. Most resins are stated to be for X grains/cu.ft. of resin which is independent of the feedwater.
The only color changing resin I've ever seen is cation resin (color change is pH dependent) and adding it to your cartridge will not get you much since anion resin is not as efficient as cation so requires more. Unless the manufacturer cut short on the anion, you would exhaust your anion while the cation is still good, so the color would not change. TDS meter is better to see first break (unless of course even better is if you add a silica or sodium analyzer to the effluent of the resin; silica and sodium are the first to break through. Not practical for the home hobbiest)

 

[DeathWish302]

Deathwish,
It is unusual for a company to state # gallons throughput on resin when the quality of the feedwater is the determining factor. Most resins are stated to be for X grains/cu.ft. of resin which is independent of the feedwater.

Here's Spectrapure's claim:
http://www.spectrapure.com/St_MaxCap_D2.htm

The only color changing resin I've ever seen is cation resin (color change is pH dependent) and adding it to your cartridge will not get you much since anion resin is not as efficient as cation so requires more. Unless the manufacturer cut short on the anion, you would exhaust your anion while the cation is still good, so the color would not change. TDS meter is better to see first break (unless of course even better is if you add a silica or sodium analyzer to the effluent of the resin; silica and sodium are the first to break through. Not practical for the home hobbiest)

Sorry, I wasn't clear before. Since I will lose a little resin when recharging, would mixing a couple Tsp of some mixed-bed, color-changing resin I have from a BFS canister work? Basically, can you mix resins w/o concern of final performance.

I bought the Rooto NaOH and Muriatic Acid from Ace last night. Might give this a try tonight or later this week and post results. Anyone find a 'superior' NaOH, or are they fairly equal for resin recharging?

 

[Buckeye Hydro]

Spectrapure is right, but I can see where their answer would be a little confusing.

Many reefers use mixed bed, color changing resin. It is actually only the cation portion of the mixed bed that changes color.

Adding some extra mixed bed resin to another cartridge should be fine.

Russ

 

[yardboy]

Technically, Spectrapure wasn't misleading, and if your RO effluent had <20 ppm and you only got 400 gallons then I'd say you got a bad cartridge and should be reimbursed. On the other hand, I had inexpensive tds meter that read 0 ppm when it was actually much higher, and only figured it out when I started having algae problems and tested with independent meter.
Adding extra resin, as Buckeye said, shouldn't be a problem.

 

[Jacob D]

dngspot - great thread. Thanks for sharing your techniques and keeping it updated over all this time. I have a few questions for you....

First, you mentioned using 5 gallons a day; by that do you mean that you use about 5 gallons of RO/DI water daily? That's about what I use, excluding water changes. At this rate you're getting about 3 months of use on your DI resin? What amount/volume of resin are you using?

Which leads to my next question - which resin cartridges are you using (do you have a link to anything similar on the web?)

I believe somewhere you mentioned that you're using two resin cartridges, you run them in parallel, correct?

Are you still keeping the cation and anion media separate?

Lastly, have you come up with any new/better methods for separating the media? (I have not read the entire thread, just the first few pages for the most part).


Thanks again for taking the time to share.




p.s. Someone asked early on what the bulk caustic is intended for. One common use is in cleaning of food plants, dairies, etc. Clean In Place systems typically cycle hot caustic, then acid through the stainless product piping and tanks. I've had the pleasure of being sprayed from head to toe with fresh caustic solution... good thing for the safety showers. It's fun to go back to the desk in your office clothes soaking wet

 

[dngspot]

I use two standard 10 inch cartridges. They can be found here http://www.buckeyefieldsupply.com/showproducts.asp?Category=204&Sub=130 they are located at the top of the page. They hold about 1.25 lbs in each cartridge. I run the canisters in series, one after the other.
I attempted to run the resins separate and had very little success. If I regenerate the resin in advance I keep them separate, then mix before I fill the cartridges.
On page 8 is the current way I now regenerate resin. With the help of a few others who have posted here the process was refined. At the bottom of the page is a 13 step post, this is pretty much the exact process.

Good luck

 

[quagmire]

Technically, Spectrapure wasn't misleading, and if your RO effluent had <20 ppm and you only got 400 gallons then I'd say you got a bad cartridge and should be reimbursed. On the other hand, I had inexpensive tds meter that read 0 ppm when it was actually much higher, and only figured it out when I started having algae problems and tested with independent meter.
Adding extra resin, as Buckeye said, shouldn't be a problem.

Can you recommend a reliable hand held TDS meter?

 

[Buckeye Hydro]

The TDS EZ, TDS3, or COM100 all from HM Digital, have good reputations.

Russ

 

[quagmire]

Thank you for the quick reponse

 

[DeathWish302]

The TDS EZ, TDS3, or COM100 all from HM Digital, have good reputations.

Russ

Hey Russ,

Would you say the TDS3 is a 'cheap' meter? I've been using this meter for all my measurements in the last 2 years with calibrations every 3 months. This $18 meter has drifted the least out of any other piece of equipment I use and is the most inexpensive of all. I still say that the MaxCap system is questionable at best in the true $ vs. longevity and a DI recharge for $2-3 every 6 months beats $60 of new resin every year.

 

[Buckeye Hydro]

good to hear re your tds3!

 

[wooden_reefer]

I want to know if DI resin is the same as, or similar to, water softener resin.

 

[dngspot]

I read someplace that the resin in softeners is only cation. At least this is what I remember, I may be wrong.

 

[Buckeye Hydro]

You're right. The cation resin in a softener is also different in that it is designed by be recharged with sodium, rather than an acid like the cation resin we use more commonly in our mixed bed resin.

Russ