RO/DI. . .what defines a good one?

[IslandCrow]

What should I be looking for in an RO/DI unit? Obviously, I want it to remove as many contaminants as possible, but can I take the numbers they give at face value? Also, are there any other gotchas I should be paying attention to like type and cost of filtration media?

 

[Konadog]

I would stay below the 100 gallon per day, as the 100 GPD have a lower rejection rate on the RO filters. I would also check to see that they have a tru Dow Filtec Membrane for the RO. If you can, get a refillable cartridge on the DI filter, that way you can refill your own later when it is exhausted.