Pickle Watermaker

[captden]

Now it's time to put my watermaker to bed for the season the book I have tells me to use sodium metabisulfite to flush out the membraine for long term storage but it doesn't say how much to use or where to get it. I was wondering what other cruisers use to pickle their units. This is a 500 gal per day unit.

captden

[Therapy]

propylene glycol.

Durvet Inc D Propylene Glycol Gallon - 01 dso1183#

[allanpeda]

Originally Posted by captden

Now it's time to put my watermaker to bed for the season the book I have tells me to use sodium metabisulfite to flush out the membraine for long term storage but it doesn't say how much to use or where to get it. I was wondering what other cruisers use to pickle their units. This is a 500 gal per day unit.

captden

Google came up with this:
Water Purification Storage and Disinfoection of a Reverse Osmosis Membrane

MEMBRANE STORAGE AND DISINFECTION PROCEDURE

System or Membrane

Use RO permeate (if possible) water to make a solution containing 2% (by weight) sodium bisulfite and 1 ounce sodium metabisulfite per gallon.
Flush and fill the system with this solution, then drain thoroughly.
Seal the system.

Long term storage of membrane only

Use RO permeate (if possible) water to make a solution containing 2% (by weight) sodium bisulfite and 20% (by weight) of glycerine.
Soak the membrane in this solution for 30 minutes.
Drain excess and seal the membrane in a plastic bag.

A 1993 report details procedures as well. Google "Chemical Pretreatment For RO"

Which is in line with the prior posting about propylene glycol.

[senormechanico]

Sodium Metabisulfite is cheaply obtained at any wine or beer home brewing store.
Here's where I buy my stuff:

Home - Northwest Brewers Supply

[Tellie]

I agree with Therapy. I've become a firm believer in propylene glycol for storing watermakers. Things to remember are that you want to use the -100 which is a 50/50 mix not the easier to find -50. PG -100 is not only softer on membranes but will store a membrane longer than sodium bisulfite or the powderd solutions the major manufacturers supply. Also PG helps lubricate and keep supple internal parts of pump seals, O-rings valves, hoses, etc. I find many times owners will leave their watermakers stored for longer periods of time than they anticipate. PG is not that more expensive than the cheaper powdered solutions, certainly cheaper than watermaker repairs the next season. Also, never ever use sodium bisulfite in a Spectra watermaker.

[captden]

Originally Posted by Tellie

I agree with Therapy. I've become a firm believer in propylene glycol for storing watermakers. Things to remember are that you want to use the -100 which is a 50/50 mix not the easier to find -50. PG -100 is not only softer on membranes but will store a membrane longer than sodium bisulfite or the powderd solutions the major manufacturers supply. Also PG helps lubricate and keep supple internal parts of pump seals, O-rings valves, hoses, etc. I find many times owners will leave their watermakers stored for longer periods of time than they anticipate. PG is not that more expensive than the cheaper powdered solutions, certainly cheaper than watermaker repairs the next season. Also, never ever use sodium bisulfite in a Spectra watermaker.

I just have a couple of questions, how much should I use and do you just pump it into the system and leave it in and then flush it out when it's time to run the watermaker next season?
captden

[Tellie]

Originally Posted by captden

I just have a couple of questions, how much should I use and do you just pump it into the system and leave it in and then flush it out when it's time to run the watermaker next season?
captden

Two gallons should be enough to start for a 500gpd unit. You don't mention which brand of watermaker you have, refer to the manual for storage procedures for your make. But the simple answer is that the PG will be circulated throughout the system for 30 minutes while the unit is running. This is done by setting the valves in the correct position and routing the intake and brine discharge into a five gallon bucket that holds the two gallons of PG. 30 minutes should be more than enough run time to make sure the membranes surface is completly covered with the PG. The PG stays in the unit. This will store your unit for a year. Though you can go longer, I would always recommend that if you have not re-commisioned your unit within a years time that you flush the system and re-store it with fresh PG. Important to remember is not to run the system under pressure while both storing the system or re-commisioning it at a later date.

[jlsail]

Hi
Does anybody know if you can use potassium metabisulphite instead of sodium metabisulphite? Looking on the internet it looks to do the same job, here in Las palmas it seems hard to get the sodium type.

johan