DI or Not to DI -THAT is the question !

[DiverDude]

I was going to buy a 2-stage RO unit but got a good deal on a 3-stage RO/DI unit with a built-in TDS meter. A good part of the justification for this purchase was that I'm planning on getting rid of our Culligan water service and replace it with our own cooler and then refill bottles from the RO system.

I've done a LOT of reading on this in the last week or so and while RO seems fine for drinking, RO/DI water is one step better for the tank (takes EVERYTHING out (even the good stuff) and then you just put back exactly what is needed via a quality salt).

BUT....I'm reading that DI water isn't the nest thing for people to be drinking.

I'm contemplating leaving the DI cartridge out of the system and running it like that. Reasonable compromise so we can still drink it ?

Opinons ?

[sphelps]

Well I run DI for both the tank and drinking water. I've also heard DI isn't the best for drinking but not sure why, I do know that nothing in the water is "good" for you, that's just a cover up for crappy water.

Either way I can offer a solution. For tank water, hook up the system as presented and run the line to the tank. For drinking water, tap into the line that runs from the RO to the DI. If you have a pressure storage tank connect it to the same location as drinking water (before DI). This way you got DI water for tank and non DI for drinking.

[DiverDude]

I haven't examined teh unit closely enough to know if I can reasonably plumb in between the cartridges but I'm pretty handy so I can probably rig something.

Based on your suggestion though, you think there is merit in running a DI stage for the tank -or is RO 'good enough' ?

[MrsBugmaster]

you can always get a RO bypass valve for the unit and then you can have both:biggrin:

[DiverDude]

you can always get a RO bypass valve for the unit and then you can have both:biggrin:

Sounds plausable -where might one find such an item ?

[fkshiu]

An RO bypass is simply a T connector after the RO stage with one end going to "Drinking Water" and the other going to the DI cartridge.

I'm a firm believer in using both RO and DI because each stage better at dealing with certain impurities than the other one - you want to be sure exactly what you have in the end and RO alone can miss some ions that DI would pick up.

The whole "DI water" is bad for you thing is a myth IMO. Drinking pure DI is not good simply because it tastes like crap and not because it will somehow suck minerals from your body like a vampire as some believe. That's why RO/DI drinking water systems always have a "taste cartridge" consisting of coconut husks post-DI to remineralize the water. In fact, most bottled water that you pay through the nose for is simply remineralized RO/DI water. And re-mineralized RO/DI water is just that: water. Putting water through DI doesn't forever taint the water from human consumption - that's just silly.

[globaldesigns]

Hey Diverdude,

As you know I only have a 2 stage filter with membrane. So a basic RO filter system for my big system. I never have had a problem and my final TDS is only 1-2 ppm. So you don't need it in my opinion, but if you can plumb things to run the DI for the tank and then have RO for drinking, then do it that way.

If you have it, use it!

[DiverDude]

After much research I do believe that DI water does pull some salts and minerals from your body. However, while we get some of our RDI from water, it's a VERY small percentage. The vast majority comes from food and if you are healthy and well fed, this doesn't appear to be a significant health issue.

TASTE is another matter I hadn't really considered ! Coconut husks ? Really!? Jeez !

As to the bypass, I had (mis)understood that it was a valve of some sort and not just a "T".

Finally, the DI cartridge doesn't seem to be a huge expense (~$29) and with just a 29 Gal tank, I don't see myself going through lots of them so I guess I'll run the DI cartridge for now and see how it goes. The tank will get RO/DI and we'll drink plain RO.