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RE: R/O filters



Roger Miller is wondering about getting an R/O filter unit for his water
supply.

Roger, I don't know what is in New Mexican water that is so bad, but unless
you can find a productive use for the reject water, it could be an expensive
proposition ecologically speaking. I have a 50 gal/day TFC unit from Kent
Marine and, at least under the conditions I am forced to operate mine, I'm
lucky to see a 1:5 ratio of "good" to "reject" water. Living on the shores
of one of the largest reservoirs of fresh water on the planet (the Great
Lakes), I'm not too worried about wasting water, as the water which goes
down my drain is headed back into Lake Ontario anyway, but you live in a
desert, and water is a precious thing there.

R/O units are sensitive to a number of factors:

Temperature and pressure of the input water - if you can't supply the unit
with water at it's "design" load, the amount of "reject" water will go
through the roof (at least it does in my case - I live on the 22nd floor of
a high rise and the water pressure is not all that great).

A lot depends upon what you want to get out of the water - most of what the
unit is taking out (minerals) are going to have to be put right back in to
make the water suitable for fish and plants.

Storing R/O can present problems, as you are expecting. R/O water contains
no chlorine to prevent the growth of bacteria, so your storage facilities
are going to have to maintained very carefully to prevent it from becoming
fouled with some "bugs" that could potentially do some damage to you or your
fish. You have a house (I'm in an apartment), so your options might be more
varied than mine - Rubbermaid makes a variety of plastic storage containers
with lids - that's what I use.

The cost of replacement parts - you have to figure in the cost of the
prefilter and the carbon filter (all TFC units require the use of both) and
also the cost of replacing the R/O membrane itself every couple of years,
and depending upon where you buy it, replacement membranes can cost almost
as much as the complete unit did in the first place.

Once possible alternative, depending upon what you want to remove from the
water supply, could be Poly-Bio-Marine Inc.'s Kold Ster-il System. It won't
remove minerals or affect alkalinity, but it will take out volatile
organics, pesticides, organics, chloramines, organic bound phosphates and
silicates, amines, parasites and bacteria, etc. A big plus is that there is
no "reject" water - what comes in "bad" comes out the other end "good". The
harmful materials stay in the filter media which you must replace on a
regular basis ($$$). They have a web-site (http://www.poly-bio-marine.com/),
so check it out.

James Purchase
Toronto