Cleaning watermaker membranes?

[oceanjake]

I have an 800gpd watermaker aboard my boat with 40” or 48” membranes. I’ve never owned a watermaker but can imagine that without regular use they will not last long, so I’ve been running the thing every couple of weeks to make 20 gallons or so at a time. I have noticed reduced performance over time, and this week a hose fitting went bad. This weekend when I replace the hose, is there any point in removing the membranes for a physical cleaning or inspection? If so, what is involved? Thanks.

 

[sixty]

As far as I know there is no cleaning them and they have a fairly short life if not pickled when not in use. They also have a very short lifespan when used in dirty water so if you have been running them in your slip its probably done them in.

How old are your membranes?

 

[Pascal]

They cant be cleaned but with prefilters you can run them in your slip and wont damage them. Oil is a killer for membranes but if your pick is low enough, it shouldnt be a problem even without an oil filter.

Most WM have a fresh water flush whcih needs to be run every 7 to 10 days. No need to pickle the membranes unless the boat is going to be shut down for weeks or months as long as the fresh water flush is automotic and nobody turned the breaker off...

 

[SEVEN]

Agreed, cannot clean other than flush. I have the reverse osmosis system at home and have to replace the membranes at least once a year.

 

[oceanjake]

Sounds like I’m due for membranes. My watermaker has a cleaning flow direction but I don’t know that it is freshwater and it’s definitely not automatic. I’ve owned the boat for a year and have been less religious than I should be about running it. I don’t run it in the slip because that’s just nasty. What are the symptoms of membranes going bad? Just reduced flow?

 

[SEVEN]

Smell, taste, bacteria growth etc.

 

[Scarlett]

Sorry don’t agree, you can do an acid bath and an aylkali bath with the appropriate chemicals. Best procedure is to run the chemicals into the membranes as if you were pickling it and let the solution sit over night, then flush and repeat with the other chemical. I brought back a membrane that had sat for 14 years without being pickled. When I started it would not even make water and by the time I was done it was making water at 150 ppm and did so for 13 years until I sold the boat. John

 

[SEVEN]

You will have to walk me through this one John.

 

[oceanjake]

Tell me your secrets, wizard. It doesn't look like the membranes are TOO bad. What are the cost of the associated chemicals? What are they?

 

[tonytrakovich]

As others have said, flushing is the key. Your watermaker will make water at different rates depending on raw water salinity and water temperature. What line burst in your system? If it was a product water line, you may have an o-ring or a membrane failure. Or a plugged brine return line.

 

[Scarlett]

At the time we did the cleaning the chemicals came from Pur, which is now Katadyne. They are powders and mixed with water. One is an acid and one is an alkaline (not sure on spelling). They were introduced to the membrane as you would a pickling solution. The key seemed to be to let them sit in the membrane overnight before you flush the membrane. The instructions did not say to let it sit ove night, I think they said to circulate it for a time then flush, but the soaking seemed to work better and circulation. Actually I looked at Katadyn’s web site and they do suggest soaking overnight. Southern Seas Marine online has both cleaners available. John

 

[captainwjm]

Some informative videos on these topics here:

http://cruiserowaterandpower.com/Water_Maker_Videos.php

 

[Mike36c]

Chlorine is also a membrane killer, be sure to carbon filter any water used for membrane flushing.

 

[Scarlett]

Agree with Mikes comment, most water makers come with a carbon filter on the back flush line. If not be sure to either use water that was produced by the water maker or distilled water for flushing or cleaning. John