Water purification question

So I have a decent hybrid water fed pole that I picked up used, but I don’t have a filtration unit. I don’t do many windows at all but I needed to last weekend so I borrowed a buddies wash-it pro. we have tds readings from 150 to 200 everywhere I service. i tested out of his ro alone at around 5 or 7 tds, and after the di at 0000. my question is, if i wanted to do the occasional window job with my wfp, would I really need a di unit, or would an ro be sufficient if it gets us down under 10 tds??? if ro is sufficient why don’t any of these major pure water window companies sell one. I can find a few di only units, and dozens of 2 stage 3 stage, and 4 stage units, but i can’t find any 1 stage ro, or 2 stage carbon/ro. Any help??

If your not going to be using it everyday & TDS is low, a standard DI tank will do. I’ve used one for years. Also have one I want to sell if your interested.

Yea all you need is a di tank. Buy a 1/2 or 1 cubic foot tank from window cleaning resource and at that Tds you will get a lot of life out of it.

if you are not going to buy a cart, check locally to see if anyone rents them

So going with just DI is better than going with just RO? What’s the reasoning. Sorry I’m just not that familiar with this type of equipment. John D, can you send me specs and asking price on your unit?

If you will using it periodically & TDS is fairly low in your area a DI tank is fine. You can clean up to 1,000 windows with it. Don’t get me wrong, you can use whatever you’d like it & the glass will come out clean. An elaborate unit would be overkill IMO. Plus the cost factor.

If you have a Culligan near you, you can even rent one to see if it fits your needs & what direction you want to go in.

If you even would be saving money in the long run with just ro, you might just as well get what takes you to 0 tds for the small amount of WC you do.

Can anybody do a thorough comparison between just RO, just DI, and RO/DI combo? I’m trying to weigh up front costs, and cost per gallon after that. My tds is 200. Here’s the info I have now.

DI ONLY 1/2 cubic ft tank initial cost: $207
DI ONLY 1 ft refill: $178 lasts 753 gallons @ 200tds = $.24per gallon

RO ONLY initial cost: $???
RO ONLY membrane replacement: $?? last ??? gallons @ 200tds = $??? per gallon

RO/DI wash it pro initial cost: $1800
RO/DI wash it pro refills: ??? lasts ??? gallons @200tds = ??? per gallon


Check out the wcr forum. There are a ton of threads you can go through to get your answers. I’m not much of a window cleaner so can’t help you with the numbers you are looking for.

I agree with John Devine. WCR has a lot of specific discussion about this.
I will say that from every thread I’ve ever read, you will definitely do the best with RO/DI if your area’s TDS is usually around 200. RO alone may not consistently get you to a low enough TDS to avoid spotting at that reading. DI alone will,but you’ll burn through it too fast.

Where can I get a DI refilled at?

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Sent from my iPhone using Pressure Washing Resource mobile app