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Originally posted by PaintGuru
Ok here is the thing. My RO/DI unit came with this pipe-bomb looking container for the DI. It is not a cartridge, it appears to just be a cyl. with resin in it. So I dont think I can utilize the cartridges. I need to check prices yet, but I thought I could get it cheaper somewhere...I may be wrong though.
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Paint - I know your post is old, but in case you haven't got this resolved yet...
Yes - many of the lower cost RO/DI systems out there come with a DI cartridge as you describe. The are cheaper to include as new equipment on a new unit, but aren't cost effective once you need to refill them - because you can't! So all and all they are something to be avoided. You'll note that this is the type of cartridge sold on many of the "blue light specials" on ebay. Sounds good if you've never owned a system before, but costs much more in the long run.
In a case like yours, what you can do is add a
http//www.buckeyefieldsupply.com/showproducts.asp?Category=39&Sub=1
and make sure you use a refillable cartridge so you can use bulk DI resin. MUCH cheaper in the long run.
Now - if you have a refillable horizontal housing - how does that compare to a refillable vertical housing? The in-line units usually have a smaller internal volume that the standard resin cartridge = less resin = less treatment and quicker resin exhaustion.
Additionally, remember that over the life of the resin, the beads in the resin will shrink. If they shrink a little in a vertical housing, the mass of resin, affected by gravity, still remains in the lowest position possible in the cartridge. Since the water enters the cartridge from the bottom - no problem. It still has to flow through the entire mass of resin. But in a horizontal unit, when the resin shrinks and settles to the bottom of the cartridge - viola - the water entering the cartridge has a clear and open shot along the top of the cartridge to "short-circuit" the resin and flow from one end of the cartridge to the other without full contact with the resin. That's why you'll not see these types of cartridges used on the higher quality units.
HTH
Blue