Re: Reverse Osmosis Units

[huntley@ix.netcom.com (Wright Huntley )]

Fredrik wrote: 

snip...
>
>Life-expectance for RO-membranes?
>
>One thing that I've never seen mentioned is how (or if) the life-span
>of the membrane is affected by not only age but also amount of water
>that's passing. Something tells me that you "wear out" the membrane
>running it at full speed every day but no info I've found concurrs
>(only age is mentioned, 3-6 yrs if properly maintained for my unit).
>
>Wright, you say your membrane is still good after several (=?) years.
>How hard have you been using the unit? Just curious.

For a few years (I forget the exact time, but about three) it was used 
very intermittently as a source of pure water for my photo lab. Since 
then, it has been in much heavier use, for about 2+ years, for water 
for my aquaria. Some of that has been full-time use, and some has been 
50-75% on and the remainder off.

>
>The operating manual for my unit says that if it's not used for a 
longer
>period of time one should use a desinfectant to preserve the membrane.
>Will flowing water have the same or the opposite effect?

IDK, but I suspect using it inhibits bacterial attack because it is 
getting flushed, constantly. I've never left mine unused for more than 
a few weeks.

AFAIK, the end-of-life of the membrane can happen by clogging 
(production rate falls off) or by losing permeability due to corrosive 
effects of bacteria, your source water, etc. With permeability loss the 
tds go up. I think it varies widely, with the local conditions being 
most important.

BTW, I concur with the suggestion to buy from Ron Harlon. I have never 
heard of a customer complaint about his units, and you *can* get 
service. I despair of finding a Price Club where I can buy a 
replacement membrane.

Wright


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Wright Huntley (408) 248-5905 Santa Clara, CA USA huntley@ix.netcom.com