RO DI help please

Some guy locally is selling me his RO DI.. He bought it about a year ago, tested it out but didnt have enough water pressure so he didnt want to get a booster pump and well after sitting in his garage he is selling it to me for 40 bucks, filters are white and seem new.. Now question is, is the membrane and DI okay since it has been sitting for a few months??

 

Only way to know for sure is to test it out, the membrane may have dried out. Also you may need to change all the filters if they weren't all emptied out before they were put away. If you are replacing the DI, you should also look into a new vertical DI canister. The horizontal types are not recommended as the water can channel through without the DI having time to do its work.

 

Well as for the DI thats simple i can just mount it vertical on a wall or so but as for the membrane by the looks of it, water is still in the system and shouldnt have dried out now with that said....if i do have to make filter changes, is it still worth it ? he said he paid like 300 for it at the LFS

P.S its better than the 3 stage i have now which needs membrane, filters and add Di

 

I would say that you could get a much much better unit than that for much less than $300 new, I would say you could get a quality new unit for $200, maybe less. I would say that no it's not better than the unit you currently have. Do you have DI on your unit? If not just buy a DI canister and add it to your unit along with some new filters.

 

Also just mounting those DI canisters vertically wont cut it. They are completely different canisters in looks and function.

 

Well i mean i didnt really want to spend the 200 so for $40 on this seems nice i might take the risk and test it when i get it, even if it needs new anything im still at lets say $90 spent.. My unit now is old with only 2 canisters (sediment/ Carbon)and a membrane.. All of them are empty so i need to buy those and add a DI plus($$$membrane $40) the canister isnt clear and needs new lines do to mold..I spent a lot of LEDs and supplies.. RO DI isnt on my list for spending the extra cash so cheaper is better lol

 

Some bleach and a brush will look after the mold, if that other unit has been sitting unused, you'll likely be looking at the same situation. It's up to you, if you decide to go for it let us know how you make out. Just remember if it needs new filters and membranes you are looking at another $50 or more, plus the DI canister. Sorry I only mention that, because it almost puts you at the price of a new quality unit .

EDIT: I just went through this with a unit I had that sat unused for a year, I had to tear everything apart, replace everything and disinfect the unit.

 

The only way to know if the membrane and DI are good is with a TDS meter.
Test the tap water TDS, RO only TDS and final or RO/DI TDS after the system has been running an hour or so to flush it out well.

If the RO only TDS is 95-98% less than the tap water TDS then its probably OK. If the RO/DI TDS is 0 or very near it then the DI resin is OK but I doubt if it is since resin has a short shelf life even when vacuum sealed and properly stored.

That unit sells for around $80-$100 online and is pretty low end but if it works for you then you did OK. You can get a Spectrapure 90 GPD reef quality system with a treated and tested RO membrane, 0.5 micron absolute rated sediment filter, 0.5 micron 20,000 gallon carbon block and full size 20 oz vertical refillable 10" DI filled with reef specific SilicaBuster DI resin and an inline presure gauge and capillary tube flow restrictor for only $120 so you may want to compare the cost of replacement filters before diving in though.
MAXPURE MPDI SYSTEM

 

I picked mine up off Craigslist for $30 with 4 gal pressure tank 3 canisters and ro canister. Paid air water ice about $90 for 75 gpd membrane 10-5-1 um filters and DI canister setup.
So for $$120.00 I have a 5 stage rodi setup with reserve tank. Just ordered new filters after a year. I say go for it and build your own. It's a good start and you have spare canisters from your existing unit

 

+1 on the Maxpure. I got this system about a month ago and works great. They actually mis-shipped to me just a set of filters at first, in which they let me keep both the pre-filter and carbon filter, so that was a little added bonus. For $120, really can't be beat.