Adding onto an existing RO/DI system

[AustinVines]

The tank I bought back in April came with a Coralife ro/di unit. I just hooked it up to my garden house and tested it out today. From the RO, my tds with a hanna meter are 20-25 but the reading from the DI is only 15. I read that the coralife "di" is a resin but it not the real thing. Also, this unit only comes with one carbon block and it seems a full five stage is the way to go. The unit is probably no more than 2 years old and was making water for a 75g so I don't know if the membrane needs to be replaced or not. I would need 20-25 gallons a week out of it for water changes and top-off. Here is the unit. I haven't looked at it closely enough to tell the exact model.

http://i62.photobucket.com/albums/h81/austinvines/IMG_0959.jpg

If everything is standard or could be easily swapped out, I would rather add to this than get an new unit, unless you think that is a penny wise/pound foolish idea.

TIA

[Hockeydad]

http://www.thefilterguys.biz/

[AZDesertRat]

What is your tap water TDS? Chances are if you are getting 25 out of the RO the membrane is shot along with the DI. It appears the membrane you have is a sealed unit and does not unscrew to replace the membrane. If that is the case www.spectrapure.com has those on special right now for $35 each with a matched flow restrictor. They also have pre and carbon filters as well as replacement DI resin. You are probably going to have $75 invested fixing that one up configured with the same amount of housings it presently has now. If you wanted to add anything I would add a vertical DI, thats really all you would need if you use high quality pre and carbon block filters in the two housings you have now.

[AustinVines]

TDS out of the tap is around 120. I will get with those vendors to see what I can add. Thanks for your help.

[carman9941]

spectrapure also has a piggyback with 3 di cartrages that hooks up to the first unit, so it will be a 5 stage unit