Pickling a Watermaker

[a64pilot]

Due to a family emergency I had to pickle ours in March. We are now back on the boat, but we have gone to ground to await hurricane season to pass. Plan on leaving in November.
How long is a pickling with Sodium Metabisulphite good for? Should I fresh water flush and repickle? May be tough to find RV antifreeze in the middle of Summer in Ga.

[KeelMe]

We have never pickled ours but we are rarely away from the boat more than a few days.

That being said; the manual desalinators that are meant for emergency use are typically pickled and left unused for years.

[Kenomac]

We use the recommended pickling solution from Rich at RO or the Spectra solution. Both are good for more than a year. Don’t know about RV antifreeze.

[a64pilot]

It’s a Cruise RO, pickled IAW the instructions, the instructions say it’s good for extended periods, I didn’t know how long that was, nor do I know if consumer pickling is the same as Dow Corning does etc.
I had read here that for extended intervals food grade propylene glycol (RV antifreeze) was better, but didn’t know why.
I’m just doing Boat maintenance and wouldn’t mind going the RV route, it’s easy and not expensive and I can get it on Amazon.
Should I?

[robert sailor]

The new chemical for Spectra is supposed to be good for 6 months and the RV stuff is good for a year but I've used the standard chemical for close to a year without any negative results. The RV stuff is supposed to be the best really long term solution. The only downside is you have to flush it for many hours before you can make good water again.
Years ago I used the standard Spectra chemical after I sold my boat and the new owner never fired up the water maker for over 2 years and it worked fine with the same specs it produced when I had it so I think there is lots of slack in the recommendations to allow for screw up operators.

[lamadriver]

Youll be fine with the Sodium Metabisulfate....... I woudlnt bother, re pickleing. if your water maker was properly flushed with fresh water , it can go 60 + days with out having to pickle.

[a64pilot]

Originally Posted by lamadriver

Youll be fine with the Sodium Metabisulfate....... I woudlnt bother, re pickleing. if your water maker was properly flushed with fresh water , it can go 60 + days with out having to pickle.

Total time pickled will be closer to 8 months, 240 days.
It’s been pickled about 60+ days now, won’t do into regular use until around Nov.

[lamadriver]

What i was trying to say is you can easily go 60 days with out using it and with out picking it if you flushed well after the last use.

I had mine pickled for 9 months when i did the refit. no issues.

I wouldn't bother re pickeling it . 8 months will be fine, just flush it real good when you go to re commission.

[a64pilot]

OK got it.

[Tellie]

I'd be careful leaving any watermaker either un flushed or un pickled for more than two weeks. Sodium Bi is fine for most watermakers, never in a Spectra. PG can be had at West Marine. If they don't have it in stock they can have it delivered usually by the next day. I far prefer PG over the pother pickling solutions. Not only will it pickle longer 2+ years but it better protects the internals of the watermaker system better which is more important than the membrane cost wise.

[a64pilot]

Way mine is pickled is you bypass the HP pump, only membranes, their housing and the low pressure boost pump I believe is pickled, and the filter as well, forgot them.

Is it the HP pump you mean by protect or these other components?
I don’t mind pickling with PG as it’s easy and inexpensive.

If I pickle with PG, should I very thoroughly flush with fresh water first?

[a64pilot]

OH, PG I think comes in different strengths?
Use the -50 and dilute by 50% with chlorine free water?

[SV THIRD DAY]

Originally Posted by Tellie

I'd be careful leaving any watermaker either un flushed or un pickled for more than two weeks. Sodium Bi is fine for most watermakers, never in a Spectra. PG can be had at West Marine. If they don't have it in stock they can have it delivered usually by the next day. I far prefer PG over the pother pickling solutions. Not only will it pickle longer 2+ years but it better protects the internals of the watermaker system better which is more important than the membrane cost wise.

Yes...
YES....and yes.

[SV THIRD DAY]

Originally Posted by Tellie

I'd be careful leaving any watermaker either un flushed or un pickled for more than two weeks. Sodium Bi is fine for most watermakers, never in a Spectra. PG can be had at West Marine. If they don't have it in stock they can have it delivered usually by the next day. I far prefer PG over the pother pickling solutions. Not only will it pickle longer 2+ years but it better protects the internals of the watermaker system better which is more important than the membrane cost wise.

Yes...
YES....and yes.

When using PG you need to use at least a concentration greater than 25 to 35% because PG and lower strength concentrations is not effective and can actually become a food for certain bacteria.

I would skip meta metabisulfite all together as a water make a preservative and only recommend PG because it's so much better. The problem is carrying around a bunch of gallons of that stuff sometimes isn't easy when you're a cruiser out away from the US. You can always order propylene glycol online from West Marine for like 7 Bucks a gallon.... cheap and easy.

[nhschneider]

We winterized our Spectra watermaker with propylene glycol when we left our boat on the hard in Norfolk, Virginia for the winter. When we were ready to use the watermaker again, we ran it with the pressure relief valve open for about a half-hour before making water.

I have been interested in trying polyethylene glycol as a pickling compound as it is very similar chemically to propylene glycol and is often prescribed by doctors for their patients (I had to drink a bunch of it before I had a certain medical procedure - the embarrassing one). If possible, I’d prefer to pickle my water maker with something that’s designed for human consumption rather than something that has labels on it that say it could be harmful if ingested.

Fair winds and calm seas.