What are the disadvantages of using "just" RO water instead of RO/DI water?

[JusJim]

I"m fairly limited on space to hook up a RO or RO/DI unit along with the space to store large amounts of water for a long time.

I found a General Electric RO unit that makes up to 10 gallons of water a day, and has it's own storage tank (Maybe 5 gallons or so).

The unit would install right under your sink and could also be used for a convenient drinking water unit also.

What are the advantages of RO/DI water over just plain RO water?

The tank is a 65 gallon so this amount would work great, since I could fill a few 5 gallons buckets in a couple days to do an adequate water change, and would always have water available for a top off.

TIA, Jim

 

[bertoni]

That all depends on what's in your water. DI will remove most ions that the RO misses. If the input water is clean enough, DI won't make much difference. Unfortunately, knowing what's actually in your water is difficult.

 

[JusJim]

So does the RO only take out the phosphates?

 

[bertoni]

RO sorts out ions, particles, etc, above a given size, with somewhat varying efficiency depending on a number of factors. So RO will remove 90-95% or more of the contaminants in question. The question is, what's in the part that the RO filter missed.

Here's a typical rejection rate spec:

http://www.dow.com/PublishedLiterat...seps/pdfs/noreg/609-01020.pdf&fromPage=GetDoc