RO/DI websites or pricing

[caferacermike]

I've been asking about the "koldsteril" brand of filters, essentially a DI only set up years ago. Folks were bashing them back in the day. They were a "zero waste" type filter. I see now that some folks think they are the new "it".

[BuckeyeHydro]

Anyone see the "Water Saver RO/DI" systems? Looks pretty interesting.

There are two RO membranes. But, the waste water from the first feeds the second membrane. Thus, less waste water. Sounds like a good idea to me.

Probably could retrofit an existing unit to do this, too.

A word about some of these systems:

When you plumb two membranes in series (waste from first feeding the second), they act as a single long membrane. So if you plumb together two 75's, then you functionally have a 150 gpd membrane.

Regardless of membrane capacity, you probably already know that your should have about a 4:1 wasteurified water ratio.

So if you plumb together two 75's, and use a flow restrictor intended for a single 75, you'll end up with relatively more purified water and relatively less waste water. You'll be below 4:1. Will you "waste" less water? Sure.

You can do the same by over restricting (going below a 4:1) with any membrane. You could use a 75 gpd membrane with a 50 gpd flow restictor, for instance.

But you will also shorten the life of the membranes. Keep the ratio at about 4:1. Its the "waste water" (called "concentrate" or "brine") that flushes the membrane to keep it from clogging with all the funkage the membrane doesn't allow to pass through.

A funny aside: You'll see some RO systems advertised on the auction website that hype their special "self-flushing" membranes. Buyer beware. All RO membranes are "self-flushing." Its a routine part of RO technology.

Russ

[Kyle46N]

PurelyH20 is another option. I bought mine from them and its been great. Not too expensive either.