propylene glycol source

[patfarrell1949]

Wondering if anyone has used "Peak Sierra full strength concentrate antifreeze + coolant" for watermaker storage?? I found this product at a TrueValue store in Grenada where alternatives (RV antifreeze etc. may be hard to find). Ingredients listed are: Propylene Glycol (57-55-6) and Water (7732-18-5). As an antifreeze it shows a requirement to dilute 50% with water for -26F protection so this would seem to be truly a full strength concentrate. I know I don't want an ethylene based product and this one seems to be OK but I wondered if anyone has any real experience?
Also, do you know how to treat the system...just circulate a full strength or 50% solution for a few minutes before closing up?
Thanks for any & all input.

[newhaul]

Originally Posted by patfarrell1949

Wondering if anyone has used "Peak Sierra full strength concentrate antifreeze + coolant" for watermaker storage?? I found this product at a TrueValue store in Grenada where alternatives (RV antifreeze etc. may be hard to find). Ingredients listed are: Propylene Glycol (57-55-6) and Water (7732-18-5). As an antifreeze it shows a requirement to dilute 50% with water for -26F protection so this would seem to be truly a full strength concentrate. I know I don't want an ethylene based product and this one seems to be OK but I wondered if anyone has any real experience?
Also, do you know how to treat the system...just circulate a full strength or 50% solution for a few minutes before closing up?
Thanks for any & all input.

I get mine from the local rv dealer but any propylene glycol will do the job full strength .

Just have to run for about an hour to completely flush it out after . BTW I have a powersurvivor35 so you will likely not need to to flush for that long .

[Tellie]

Too many protective additives meant for engine protection that will not mix well with the membrane. As Newhaul mentions. RV "Pure" PG-50 works best.

[patfarrell1949]

Thanks for these replies. I would prefer the RV version for the reasons mentioned however I don't think it is available here in Grenada and since I'm leaving the boat in a few days am looking for the next best alternative. I'll be back in 7 to 8 months...the two alternatives are to pickle with regular sodium metabisulphite which I have here or use the Peak antifreeze and take the risk of damage from the additives mentioned. Any thoughts on which approach presents a lesser risk??

[noelex 77]

Starbrite products are readily available in Europe.

They make a couple of potable water antifreeze solutions. This is their premium product:

-100 Non-Toxic Premium Anti-Freeze - PG

Is this suitable for watermaker (Spectra) pickling?

[patfarrell1949]

Thanks noelex 77 and I think the STARBRITE product is the same as the Peak product I found here in Grenada...made for engine cooling systems and nontoxic but also with various additives to prevent/reduce corrosion inside the engine. The RV version has no additives for corrosion protection (at least I don't think so) which might harm the membrane. I guess that's the question...will the additives do harm to the membrane?
And to make this easier (I hope) my 2 membranes will be stored outside the watermaker in storage tubes holding only the membranes and whatever preservative I choose. Therefore I'm not concerned about possible harm or benefit to the rest of the system.
So does anyone have info regarding what the possible harm to the membrane might be from the corrosion inhibiting additives in the Peak antifreeze or should I just take my chances with prolonged storage in the regular preservative??

[thinwater]

Originally Posted by Tellie

Too many protective additives meant for engine protection that will not mix well with the membrane. As Newhaul mentions. RV "Pure" PG-50 works best.

The long liofe versions contain percent levels of dicarboxilic acids, which can be a problem with certain polymers. This is why early Decool formulations had some leak problems (reformulated now--no longer applies to Decool and vehicles). But I don't know about watermakers.


I would be inclined to order pure PG, not knowing what RV formulators add or trusting the quality.


(20 years expereince in the antifreeze business as a chem E)

[wsmurdoch]

You might check on USP propylene glycol at a vet office or pharmacy. It is a common digestive med for cattle and goats. It comes in gallon jugs and is 99.9% PG.

[HeywoodJ]

Originally Posted by wsmurdoch

You might check on USP propylene glycol at a vet office or pharmacy. It is a common digestive med for cattle and goats. It comes in gallon jugs and is 99.9% PG.

Also used in cosmetics, and in the extraction of compounds for vaping. Don't know what Grenada is like these days, but you can get a gallon of USP PG at many head shops.

There was a thread a while back on this same subject but downwind in Curacao, the OP was able to find some on-island at a cosmetics place that packaged island botanicals for the tourist trade.

And, another word of caution on even the RV stuff, I got some that claimed it was suitable for potable water systems, contents PG and water, but when I opened I could easily and readily smell the alcohol. No mention whatsoever on the container or the website, but finally found an SDS that said it "could contain" either PG or alcohol, or both. So, don't trust the labels on the packaging.

[jamhass]

Which Watermaker? I believe P-G is fine for all, but the Sodium-MBiS is specifically NOT recommended in Spectra WMs (and can damage the Clarke pump). -- but Tellie will chime in if I have it wrong, I am sure.

[patfarrell1949]

Thanks to all who replied to my query. Here's what I have done: I fabricated storage containers from pvc pipe for the membranes only...these are Filmteck 2.5x40 inch membranes. I read through the available documentation for the Peak brand anti-freeze and determined that no alcohol or ethylene based chemicals are present and if I can believe it, nothing other than propylene glycol and water. I flushed the membranes while still installed with freshly made water and then placed them in their storage tubes. I then filled with antifreeze (no extra water) and sealed up the pvc pipe containers. Note - before shutting down the watermaker and over the last 6 months of almost daily use PPM has risen from circa 150 to 195...my belief is the membranes are starting to show age and may have been affected by recent use in some harbors.
I'll return to the boat in December, reinstall the membranes and report then what has been my experience. I also have a spare new set of membranes just in case!!
Thanks again for all the feedback.

[Mark_S.]

I am also in Grenada. I used the Peak Sierra full strength concentrate to pickle my Spectra watermaker last season after consulting with a Spectra tech. Since it is a full concentrate, he suggested mixing in only 1 gallon of the PG with the 2 gallons of fresh water (flushed) already in the system. This resulted in a mixture above the 25% that Spectra recommends. I pickled the watermaker "as is" for the 20 months I was gone due to the Covid restrictions. This season, the watermaker performed normally in quantity and quality. I have pickled our system with PG for many years. Our membrane is about 8 to 10 years old and still makes good water.

[Lodesman]

Do you honestly worry about freezing in Grenada?

[Mark_S.]

Originally Posted by Lodesman

Do you honestly worry about freezing in Grenada?

The pickling is not to prevent freezing. It is to minimize any bacterial growth on the membrane. At least that is my understanding.

[patfarrell1949]

Thanks Mark S....I'm now back in USA for the next 6 months and also don't really expect freezing conditions...either here or back in Grenada! In my case I am only trying to preserve the membranes in their separate storage containers and not really concerned about the rest of the system (should I be?). Membrane removal and reinstall is pretty easy and allows me to inspect high pressure fittings etc for leakage or corrosion...I did have a little seepage at one of the fittings. The storage containers I fabricated from 3 inch PVC pipe fit the 2 1/2 inch OD membranes nicely...I may have been able to use a diluted mixture of the anti-freeze but I couldn't see any harm in going full strength and my storage containers were full at just about exactly 1 gallon of liquid.
Hopefully all will be well in 6 months!