Watermaker Cleaning

Gypsy

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14 Feb 2004
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Sydney and Australian East Coast
www.tech-x.com.au
I have just bought a Pur Powersurvivor 35 secondhand. I have limited information about the last time it was used and or pickled, probably 3-4 yrs ago. I have the manual and will contact the local Katadyn rep for advice/parts/chemicals but I would be interested in comments from experienced watermaker users as to their cleaning history and whether there is any chance the membrane can be resuscitated.

After trawling the www I read that:
- a chemical often used for 'pickling' is Sodium Metabisulfite - any confirmation or alternatives?
- Cleaning/flushing the system/membrane to return freshwater production to normal levels is done with an alkali solution for biological fouling and an acid solution for scaling - I can't find any information about what chemical and what strength. Can anyone tell me more?
 

Marsupial

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I have just bought a Pur Powersurvivor 35 secondhand. I have limited information about the last time it was used and or pickled, probably 3-4 yrs ago. I have the manual and will contact the local Katadyn rep for advice/parts/chemicals but I would be interested in comments from experienced watermaker users as to their cleaning history and whether there is any chance the membrane can be resuscitated.

After trawling the www I read that:
- a chemical often used for 'pickling' is Sodium Metabisulfite - any confirmation or alternatives?
- Cleaning/flushing the system/membrane to return freshwater production to normal levels is done with an alkali solution for biological fouling and an acid solution for scaling - I can't find any information about what chemical and what strength. Can anyone tell me more?

The three chemicals are:

sodium metabisulphite for pickling

citric acid for the acid cleaner removing calcium

Sodium Hydroxide (caustic soda) is the alkali solution

they are all available from supermarkets or home brewing stores but these suppliers tend to be very expensive

I get mine mine from

http://www.acuchem.co.uk/page8.htm


I have no connection with this company other than as a customer


these are the instructions for my watermaker Echotec as they use standard parts these instructions should be ok for yours.

after 4 years its a gamble as to if you can regenerate the membrane but worth a try

MEMBRANE CLEANING PROCEDURE
The ECHO Tec. Watermaker must be chemically cleaned when the product water output drops by
15% of the specified amount. The frequency of this occurring will vary greatly depending upon
feed water. Fouling of the membrane will naturally occur during normal usage of the ECHO Tec.
Watermaker. Increased amounts of fouling without proper cleaning of the membrane will reduce
the performance of your water maker. A drop in production of approximately 10% is normal and
expected during the first year.
CAUTION: The use of chemicals or cleaning methods other than those outlined in the
cleaning instructions will void the ECHO Tec. warranty. Nonionic surfactants for membrane
cleaning or other chemicals not approved in writing by Echo Marine Ltd. will void the
element warranty.
CAUTION: Cleaning chemical #1 is an alkaline detergent. See warning label on side of the
container and observe all safety precautions on label.
CAUTION: Cleaning chemical #2 is an acid, a mineral scale remover. See warning label on
side of container and observe all safety precautions on label.
CAUTION: Do not mix different cleaning chemicals together. Do not use different cleaning
chemicals together at the same time. Mix the cleaning chemicals separately and use them
separately.
Note: All cleaning and preserving procedures can be done with either sea water or non-chlorinated
freshwater. However, the cleaning process is more effective using non-chlorinated freshwater.
To clean the ECHO Tec. reverse osmosis membrane mix a solution of 1.5 to 2% by weight with
warm non-chlorinated water (113° F / 45° C) in a clean plastic container.
Use 10ltr. / 2.5gal (with 200g / 2/3 container cleaning agent) for one 40” membrane and 4ltr/1gal
(with 40g cleaning agent) for every additional membrane.
For safety reasons we do not recommend to install a 3 way re-circulating valve. Disconnect the
intake and reject water hose and lead them in the plastic container. Re-circulate the solution
without pressure for up to 60 min. There will be no flow at the fresh water outlet.
CAUTION: Observe the maximum operating temperature of 113° F / 45° C. The high
pressure pump might over heat the solution on re-circulating.
It is important that the fresh water, remaining from the last flush is dumped before the reject hose is
led in the cleaning bucket for re-circulation in order to avoid diluting the solution.
Use cleaning chemical #1 first. If the performance does not improve use the acid cleaner #2 at the
same ratio and instruction.
 
Last edited:

KellysEye

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Emsworth Hants
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We use Sulfamic acid to remove mineral scale then Sodium Metasilicate to remove oil, grease, biological matter and grime. We then flush with watermaker water (bottled water will do) then run through a new Sodium Metasilicate mix to pickle it.

If you clean the membrane and it doesn't produce water with a mineral content less than 30ppm (membranes should give 10ppm but this increases with age) then you need a new membrane. You can buy a little meter that measures ppm, it's well worth having one.
 

KellysEye

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Emsworth Hants
www.kellyseye.net
>what concentration for your chemicals when flushing?

Our containers are 0.68kg and you are supposed to use that in 20 gallons of water. We use a quarter of the chemicals in 5 gallons. For our HRO watermaker you are supposed to run the chemicals through for one hour at 50 psi, or up to 20!! hours if the membrane is very dirty. It would be worth downloading a manual for your watermaker and checking exactly what you need to do.
 
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