Can a decades-old watermaker membrane be revived?

[simplify]

A boat that we are considering for purchase has a PUR (Recovery Engineering) watermaker on it that was bought new in 1990. We don't know how much it was used in the first few years of its life, but the current owner has had the boat since 1993 and has used the watermaker only a handful of times and not at all in recent years. Nonetheless, he maintains that if he now flushes that old membrane with citric acid and sodium metasilicate, he will be able to revive the membrane and it will work just fine. Is this even remotely possible? From everything I've read, the membranes do not last more than five years with regular use, and even LESS time if they are not used.

I think this is a PUR 35, but that is also difficult to determine since the model number is different because it's so old. Basically, I'm wondering if this item is a value-enhancing feature on this boat or not. Thank you in advance for any help!

[Paul L]

It is a low output, high power use (amps per gal) unit with a shot, or soon to be shot, membrane. It has value on EBay, but not a lot when it comes to purchasing the boat.

[Cheechako]

Originally Posted by Paul L

It is a low output, high power use (amps per gal) unit with a shot, or soon to be shot, membrane. It has value on EBay, but not a lot when it comes to purchasing the boat.

you might get it working but basically no value to the boat purchase.

[Boatguy30]

Tell him to take $50 off the price of the boat and he keeps the water maker.

Lots of hard parts are no longer available for the 35. I have had several and they are good units, but not worth messing with for most people.

[Tellie]

Agree with the above comments. The membrane is toast at 23 years and chances are very good that if it's never been serviced that there will be more issues as well. Does it add value to the boat? Not really. But if the guy says he can "revive the membrane" let him do it first. Take a hand held salinity tester with you when he shows you it's working.

[simplify]

Ah, that was my other question, how do I tell if it's really making drinkable water? A salinity tester, excellent. Because I wouldn't wanna drink it!

[AirBoyzT]

is a "Salinity" tester the same as a refractometer used with salt water aquariums?

[Tellie]

Originally Posted by AirBoyzT

is a "Salinity" tester the same as a refractometer used with salt water aquariums?

Though a refractometer measures salt content and specific gravity it is different from the hand held TDS test meter I meant. If you were looking to read the salt content of the sea water itself a simple refractometer would be the way to go. But to read the product water made from your watermaker a simple digital TDS meter is easier and quicker. Below are are the differences

Proper Aquarium Water Quality: Refractometers: General FAQs

What is a TDS meter and how does it work

[Dulcesuenos]

The pur 35 became the 40. They were well designed and havent changed much. Low ouput yes but you can run them off solar, our 40e draws only 1.5 amps. If its a manual one than I agree with the other posters about its value. if its electric than it has value and is worth a new membrane if you are going ti be dependent on it. If your not dependent on it than try flushing and getting it to produce.
Ps walmart sells a tds tester for $10.00 near the rv stuff or water filters for.home use I forget.

[S/V Alchemy]

Not to be critical, but I thought I was cheap...

The watermaker is not only ballast at this stage, it's an irrelevancy to the value of the boat in your calculations. Tellie's got the right idea: the current owner and prospective seller should demonstrate (which will involve finding a new membrane) that the PUR is functional and not funct, so to speak, not you. If it doesn't work (which is far more likely), off it comes from the manifest and down goes the price by a sliver, because it's worth "a sliver".