Di resin questions

[WvAquatics]

So I am looking to change my di resin. I got a cheap refill from chewy and it did its job but I want to understand di resins and get some new but better resin. I am confused about cation anion and mixed bed resins. So here goes.

I have smaller refillable tube that came with my rodi. Pic 1 attached. So what do resin should I use. Should I run one anion and one cation? Or should I do 2 mixed bed? Or should I mix cation and anion myself for both cartridges? I have seen that single bed resin work better but don't know how to set it up any help appreciated

 

[shwareefer]

Cations tend to get used up faster than anions but I still think it's easiest to run two mixed beds with TDS meter after the first one.

 

[WvAquatics]

That's my thoughts. Have you ever mixed your own cation and cation to make a mixed bed? I plan in future to add a ro membrane and 2 10 inch do resin to the waste of 1st ro membrane but for now this is what I have

 

[shwareefer]

No I haven't but you certainly can. BRS showed that silicate buster cartridges are just mixed bed with extra layer of anion on the bottom. You could certainly taylor your own cartridges in your own ratios if you knew what specific elements in your water needed the most attention. Having said that, I think any extra mileage would be small unless you had a specific excessive element you needed to remove.

 

[chipmunkofdoom2]

If you're going to go through the trouble of getting cation and anion resin and mixing them, just run them separately. Without extensive testing that is outside the capability of most hobbyists, one resin will always be depleted before the other. Mixing the resin yourself won't fix that.

Running separate stages will be more efficient at the end of the day. I run 4 DI stages (cation => anion => anion => mixed) and I can't remember the last time I changed any of the resins. The cation resin will probably outlive me. But you need space to run separate stages. It looks like you have an under-sink space saving unit. You likely don't have the room for separate stages. Unless you have very poor water quality, it is unlikely that separate resins will be hugely beneficial to you. Running two mixed beds will usually suffice and should not be prohibitively expensive.

Two adjustments will probably benefit you more than running separate stages. First is getting DI resin canisters that are easy to refill. I've had that style and they're a major pain. Second, run the stages vertically instead of horizontally. Running horizontally allows the resin to setting and creates huge channels the water can slip through without getting deionized.

 

[WvAquatics]

If you're going to go through the trouble of getting cation and anion resin and mixing them, just run them separately. Without extensive testing that is outside the capability of most hobbyists, one resin will always be depleted before the other. Mixing the resin yourself won't fix that.

Running separate stages will be more efficient at the end of the day. I run 4 DI stages (cation => anion => anion => mixed) and I can't remember the last time I changed any of the resins. The cation resin will probably outlive me. But you need space to run separate stages. It looks like you have an under-sink space saving unit. You likely don't have the room for separate stages. Unless you have very poor water quality, it is unlikely that separate resins will be hugely beneficial to you. Running two mixed beds will usually suffice and should not be prohibitively expensive.

Two adjustments will probably benefit you more than running separate stages. First is getting DI resin canisters that are easy to refill. I've had that style and they're a major pain. Second, run the stages vertically instead of horizontally. Running horizontally allows the resin to setting and creates huge channels the water can slip through without getting deionized.

I'm not sure how to setup these cartridges vertical. I plan to upgrade to another ro membrane and 2 vertical 10 inch do and run both to into a splitter I to the 10 inch do. I will make room for it lol. I will look into just doing cation then anion for now thanks for info

 

[chipmunkofdoom2]

I'm not sure how to setup these cartridges vertical. I plan to upgrade to another ro membrane and 2 vertical 10 inch do and run both to into a splitter I to the 10 inch do. I will make room for it lol. I will look into just doing cation then anion for now thanks for info

I don't think they're designed to go vertically. The BRS DI canisters are a fine option. You may want to consider running three DI stages. While not necessary, some ions may persist after the anion resin.

I would not run dual RO membranes. There are almost no situations where they make sense from a financial standpoint or are implemented correct.

First, the RO membranes we use need a pretty specific pressure and brine to permeate ratio (incorrectly called waste to product ratio). When feeding a second RO membrane with the brine from the first, it's almost impossible to control either of those things. This means the membrane will perform poorly and die prematurely. Even in the unlikely scenario that the second membrane gets perfect pressure and brine flow, it's still getting much dirtier water than the first membrane and will fail early anyway.

Second, except for very large tanks, the tap water used by an RO system is insignificant compared to other household uses. Let's assume you have a 100 gallon tank and do a 10% water change every week. Let's also assume you use a gallon for topoff every day. This is 70 gallons of deionized water a month. Let's assume your RO unit is setup up for a brine to permeate ratio of 4:1. That means your RO system uses 350 gallons of water a month. The average family in the US uses 9,000 gallons a month. In this scenario, your RO system will account for just 4% of your water bill. Also keep in mind that your system likely has a 2:1 brine to permeate ratio, not 4:1. Hobby RO units intentionally starve the membrane of brine in the name of "saving water." For the theoretical tank above, your monthly RO usage is probably closer to 210 gallons total per month, which is only 2.3% of your water bill. Assuming your second membrane reduces your brine by half, you're only saving 105 gallons per month, or just 1.15% of your water bill. And that's if your tank is 100 gallons. If it's smaller, the real world numbers are even less.

On average, tap water costs about a penny per 5 gallons in the US. So saving 105 gallons with a second membrane would save you $0.21/month with the assumptions above. Even if your tap water is 10x more expensive than the national average, you're still only saving $2 per month with a second membrane.

 

[WvAquatics]

I don't think they're designed to go vertically. The BRS DI canisters are a fine option. You may want to consider running three DI stages. While not necessary, some ions may persist after the anion resin.

I would not run dual RO membranes. There are almost no situations where they make sense from a financial standpoint or are implemented correct.

First, the RO membranes we use need a pretty specific pressure and brine to permeate ratio (incorrectly called waste to product ratio). When feeding a second RO membrane with the brine from the first, it's almost impossible to control either of those things. This means the membrane will perform poorly and die prematurely. Even in the unlikely scenario that the second membrane gets perfect pressure and brine flow, it's still getting much dirtier water than the first membrane and will fail early anyway.

Second, except for very large tanks, the tap water used by an RO system is insignificant compared to other household uses. Let's assume you have a 100 gallon tank and do a 10% water change every week. Let's also assume you use a gallon for topoff every day. This is 70 gallons of deionized water a month. Let's assume your RO unit is setup up for a brine to permeate ratio of 4:1. That means your RO system uses 350 gallons of water a month. The average family in the US uses 9,000 gallons a month. In this scenario, your RO system will account for just 4% of your water bill. Also keep in mind that your system likely has a 2:1 brine to permeate ratio, not 4:1. Hobby RO units intentionally starve the membrane of brine in the name of "saving water." For the theoretical tank above, your monthly RO usage is probably closer to 210 gallons total per month, which is only 2.3% of your water bill. Assuming your second membrane reduces your brine by half, you're only saving 105 gallons per month, or just 1.15% of your water bill. And that's if your tank is 100 gallons. If it's smaller, the real world numbers are even less.

On average, tap water costs about a penny per 5 gallons in the US. So saving 105 gallons with a second membrane would save you $0.21/month with the assumptions above. Even if your tap water is 10x more expensive than the national average, you're still only saving $2 per month with a second membrane.

I had seen on videos you can connect a 2nd to membrane to the waste line and run it into another di champers to cut your waste down. Like here But assuming like you said waste water has higher TDS so it would ruin the ro membrane faster didn't think of that. So I'll just plan to get 2 more canister and just do 10 inch di resins so I can eliminate these smaller di catainers thanks for the input everyone. So I think I'll just do mixed bed again for both that way I can just make it efficient enough for now until upgrade

 

[EJReef]

I don't think they're designed to go vertically. The BRS DI canisters are a fine option. You may want to consider running three DI stages. While not necessary, some ions may persist after the anion resin.

I would not run dual RO membranes. There are almost no situations where they make sense from a financial standpoint or are implemented correct.

First, the RO membranes we use need a pretty specific pressure and brine to permeate ratio (incorrectly called waste to product ratio). When feeding a second RO membrane with the brine from the first, it's almost impossible to control either of those things. This means the membrane will perform poorly and die prematurely. Even in the unlikely scenario that the second membrane gets perfect pressure and brine flow, it's still getting much dirtier water than the first membrane and will fail early anyway.

Second, except for very large tanks, the tap water used by an RO system is insignificant compared to other household uses. Let's assume you have a 100 gallon tank and do a 10% water change every week. Let's also assume you use a gallon for topoff every day. This is 70 gallons of deionized water a month. Let's assume your RO unit is setup up for a brine to permeate ratio of 4:1. That means your RO system uses 350 gallons of water a month. The average family in the US uses 9,000 gallons a month. In this scenario, your RO system will account for just 4% of your water bill. Also keep in mind that your system likely has a 2:1 brine to permeate ratio, not 4:1. Hobby RO units intentionally starve the membrane of brine in the name of "saving water." For the theoretical tank above, your monthly RO usage is probably closer to 210 gallons total per month, which is only 2.3% of your water bill. Assuming your second membrane reduces your brine by half, you're only saving 105 gallons per month, or just 1.15% of your water bill. And that's if your tank is 100 gallons. If it's smaller, the real world numbers are even less.

On average, tap water costs about a penny per 5 gallons in the US. So saving 105 gallons with a second membrane would save you $0.21/month with the assumptions above. Even if your tap water is 10x more expensive than the national average, you're still only saving $2 per month with a second membrane.

Huh? Looks like you have vertical and horizontal confused. Saving water is important in areas with drought and the water consumption is controlled by the flow restrictor. There's no noticeable degradation to my dual membrane in series setup; they both lasted the full 4 yrs before being changed. It depends on how poor the supply water is.

 

[Shirak]

I run a system similar to Chipmunkofdoom2 after all the carbon and RO next is cation that goes to double canisters of anion and then to a final mixed bed. The cation resin hardly gets used up.. like ever. The anion gets used much much faster. So you run into one and then another. The second will start changing color before the first is totally used up. Hence the 2nd anion. Once the first is totally changed color it gets refilled with fresh anion DI. The partially used 2nd one now becomes the first and the newly refilled becomes the 2nd. This is the most efficient way to run DI and get the most bang for your buck and super high quality water if you have the space for all those DI canisters!

 

[vtecintegra]

I run separate cation and anion now. I think I've been through 10 changes of anion, and the cation still looks the same. So for years I was wasting almost half of my resin when using mixed bed. It's worth it to try separate to see if one is being used at a faster rate.

 

[DrZoidburg]

It's really going to depend on your source water and what you want to remove. Ex mine is cat to anion to mix. Is really effective at removing silica (depends on type of silica) around 250+tds and other elements. (confirmed with testing). I notice though it really varies on well water. Sometimes cat goes first sometimes anion. Hardly ever change the mixed bed.