Adding RO filter to old Unger dual DI cart

So I have an old Unger dual DI cart. Would it be better to just add an RO filter to it along with a couple of pre filters from home Depot or would it be better to just buy a new 3 stage system?

I have had the cart for a while. I wanted to try out wfp and so I bought the cart to test the waters. I really need 3 stage system as the DI alone only lasts through a hand full of jobs. I don’t want to spend a lot starting out as money is tight right now. Later this year I may drop some money on a better system but I want something to get me by until busy season later this summer.

I have limited room in the van and the Unger DI cart just fits standing up. Thanks for the help.

Also if I can just add an RO filter where do I get one and for how much? Thanks

We will be offering a complete 4 stage RO/DI system for $999 starting on Feb. 1st.

Might be worth waiting a week to see.


Maybe @John can chime in here with some advice for you.

Here is a kit that you can build your own system. Just use a sediment carbon filter first then the RO before your Unger DI. Tucker Carbon Filter for RO/DI Cart | 10 Inch | WCR –

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There are many ways to add a RO to your existing system.

John thanks for the info. Would the 4"x21" RO be large enough to work in conjunction with the older Unger dual DI cart? Or would I need the 40"? The 21 would be the perfect size to add to the cart.

I would recommend just adding your own ro membrane. Is there anything wrong with your dual di? If not, go for a simple housing with a ro.


Any recommendations on an RO housing?

Here are some different options depending on preference…

That’s just the membrane itself though right? Or is it the membrane and housing?

Yes, those are just the membranes that needs to go into these…

They have a few different length and thickness options as well as the actually make up material of the housing (aluminum, pvc, etc…)

Does anyone have any experience with going from a 40" membrane to a 21"?

Which RHG 4 stage?

I posted above links to all you would need to build your own RO system to go along with your DI from Unger cart. Yes you could use 2 21 inch housings and membranes if that fits your cart. I can get those for you as well. Two 21 inch membranes will work just like on 40 inch.