DI Only instead of RO/DI

[wreck]

I just picked up my "Book of Coral of Propagation" and Calfo suggested deionization as the best choice for water purification. He suggests a cation/anion DI for pure water and no waste water. I would like to give it a try because I hate wasting all that water when I make RO/DI water. If anyone does this I'd like to hear about it. I'm thinking of converting my 4 stage RO/DI to a 3 stage DI (sediment/carbon,cation, anion)and bypass the RO membrane.

Wreck

[magnetic1]

Id imagine the DI resin to go bad rather quickly...

[YBeNormal]

DI resin doesn't really go bad, it just becomes saturated and no longer effective.

 

DI only systems are near-zero waste and are actually much cheaper to operate than RO/DI units in the long run. Cation and anion resins can be recharged but doing so requires use of caustic and potentially dangerous chemicals (http://www.reefs.org/library/article/g_deutschmann_instruct.html). It basically comes down to cost vs convenience vs risk. If I needed a very large volume of water and/or if I had more free time I would convert to a DI-only unit in a heartbeat.

[davjbeas]

I am using DI only. But in a different way.

I use Dual Aquarium Pharmacueticals(Brand Name) tap water purifier units. I get 0 TDS.

Its quick and easy and compact.

Costs more to run annualy than a RO/DI unit. There is no waste water though.

 

I can make 5 gallons in 20 minutes though.

 

David B

[wreck]

Are you using twin mix bed resin DIs or seperate anion and canion resins?

 

I'm going to give it try next time I have to refill my DI. I really like the idea of no waste water, I estimate I waste 5 gallons for each purified gallon. It's not so bad in the summer when I can use some of the waste water to water the yard but now it goes right down the drain.

 

Wreck

 

I am using DI only. But in a different way.

I use Dual Aquarium Pharmacueticals(Brand Name) tap water purifier units. I get 0 TDS.

Its quick and easy and compact.

Costs more to run annualy than a RO/DI unit. There is no waste water though.

 

I can make 5 gallons in 20 minutes though.

 

David B

[YBeNormal]

Unless you plan on regenerating the DI resin once it becomes saturated, going DI-only would end up being a very expensive option. I would also expect that you would want to use a much larger DI resin chamber or, preferably, one large chamber for anion and another chamber for cation resins. Otherwise you are better off sticking with RO/DI.

[OrientBlueReef]

I'd be interested in hearing a little more about this as well. The time and lack of waste water might make it worthwhile. I have seen a couple of people with their own greenhouses use strictly DI.

[davjbeas]

This is what I use.

http://www.thatpetplace.com/pet/group/11278/product.web

 

put 2 together for perfect water. When changing cartridges always throw away the first pint.

I have been using this system for years. When buying the refill when you order 6 or more it costs around

14$ each. sometimes they go on sale cheaper.

 

David

[OrientBlueReef]

This is what I use.

http://www.thatpetplace.com/pet/group/11278/product.web

 

put 2 together for perfect water. When changing cartridges always throw away the first pint.

I have been using this system for years. When buying the refill when you order 6 or more it costs around

14$ each. sometimes they go on sale cheaper.

 

David

 

I have seen those before. When you first did it, did you buy one, test the water, and realize you needed to add a second? How often do you change the cartridges?

[Grav]

When we do a small install and we want to setup, fill and add rock in a single day, we use a 3 stage DI filter. This allows us to add water at or near ideal temp, with low TDS, very quikly without having to bring it along. We use 5 micron prefilter, 1 micron carbon block and a DI cart. The resin seems to be good for about 100 gallons... dependant on water conditions.

 

I can't see how DI only is cheaper than RO/DI but cost is relative. If you are buying "aquarium name brand" DI cartridges & paying $50 per cart that is 50 cents per gallon. That is a lot, but cheaper than buying water at a LFS. If you are buying it in bulk like I do it is not nearly that bad. But either way, you are replacing that thing every 100 gallons.

 

Another way to look at it, yes you are wasting less water, but think of all those resin trees that are senselessly slaughtered every year.

[YBeNormal]

Again, it is only cheaper if you recharge the DI resin rather than tossing it in the trash. Otherwise it would be much more expensive than a traditional RO/DI unit.

[davjbeas]

I have seen those before. When you first did it, did you buy one, test the water, and realize you needed to add a second? How often do you change the cartridges?

 

 

For years i only used the one unit. recently I figured out my product water was 6 tds. I decided to add a second one. Adding the 2nd one I got 0 tds. my tap water is around 168 tds.

when the cartridge is new the resin is green. when it all turns purple it is exhausted. I only have to change the first one when it is exhausted. If i dont change it then the second one will start to turn purple.

 

David B.

[wreck]

When we do a small install and we want to setup, fill and add rock in a single day, we use a 3 stage DI filter. This allows us to add water at or near ideal temp, with low TDS, very quikly without having to bring it along. We use 5 micron prefilter, 1 micron carbon block and a DI cart. The resin seems to be good for about 100 gallons... dependant on water conditions.

 

I can't see how DI only is cheaper than RO/DI but cost is relative. If you are buying "aquarium name brand" DI cartridges & paying $50 per cart that is 50 cents per gallon. That is a lot, but cheaper than buying water at a LFS. If you are buying it in bulk like I do it is not nearly that bad. But either way, you are replacing that thing every 100 gallons.

 

Another way to look at it, yes you are wasting less water, but think of all those resin trees that are senselessly slaughtered every year.

 

That's good to know, thanks Phil. I'm thinking of doing prefilter, carbon block, and then dual DI cartidges. I'm going to buy resin in bulk and use refillable cartridges. I'm going to give it try, I really just hate wasting all that water. I don't care about the resin trees, I never liked the way they looked anyway .

 

Again, it is only cheaper if you recharge the DI resin rather than tossing it in the trash. Otherwise it would be much more expensive than a traditional RO/DI unit.

 

Air, water, ice sells 5lbs mixed bed resin with refillable cartridge for like $40. That's enough for 4 refills. At Gravs 100 gallon rate per cartridge, that's only 10 cents a gallon. I think with a dual DI system you might be able to get more usable water by using a color changing resin and changing the first cartridge when it is fully exhausted and then placing the second one in it's place and putting a new one in the second DI chamber. I'll let you know how it goes when I get mine setup.

Wreck

[OrientBlueReef]

That's good to know, thanks Phil. I'm thinking of doing prefilter, carbon block, and then dual DI cartidges. I'm going to buy resin in bulk and use refillable cartridges. I'm going to give it try, I really just hate wasting all that water. I don't care about the resin trees, I never liked the way they looked anyway .

Air, water, ice sells 5lbs mixed bed resin with refillable cartridge for like $40. That's enough for 4 refills. At Gravs 100 gallon rate per cartridge, that's only 10 cents a gallon. I think with a dual DI system you might be able to get more usable water by using a color changing resin and changing the first cartridge when it is fully exhausted and then placing the second one in it's place and putting a new one in the second DI chamber. I'll let you know how it goes when I get mine setup.

Wreck

 

I was thinking of doing something very similar and was on the air, water, ice website yesterday looking at those resins.

[six-line]

One problem, phosphates and silica is not removed completely by just DI alone. If you have high levels of one or the other the DI alone will not cut it. RO removes it more efficiently. This is what I was told when I ask the question a few months ago on RC chemistry forum.