Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 03-04-2014, 12:23   #1
Registered User
 
nimblemotors's Avatar

Join Date: Apr 2011
Location: Sacramento, California
Boat: Solar 40ft Cat :)
Posts: 1,557
How Long Does a RO Membrane Last?

I'm not having much luck finding the answer. Seaching CF didn't help.
I've found on the internet references from 2-3 years, and also 5-10 years.
The 2-3 years seems to be when operated 24x7 in an industrial plant.

So let me ask actual boat owners how long before they had to replace the membrane?
__________________

__________________
JackB
MiniMPPT Solar Controller
nimblemotors is offline   Reply With Quote
Old 03-04-2014, 12:46   #2
Senior Cruiser
 
Captain Bill's Avatar

Cruisers Forum Supporter

Join Date: Apr 2008
Location: On the boat
Boat: Endeavourcat Sailcat 44
Posts: 2,313
Re: How Long Does a RO Membrane Last?

Mine lasted 12 years, but only 5 of that was in regular use.
__________________

__________________
Captain Bill is online now   Reply With Quote
Old 04-04-2014, 09:52   #3
Marine Service Provider
 
SV THIRD DAY's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: La Paz, Mexico
Boat: 1978 Hudson Force 50 Ketch
Posts: 3,653
Re: How Long Does a RO Membrane Last?

Dow Chemical makes what many consider to be the Gold Standard in RO Membranes and they rate their sea water membranes with a 7 year life span of 365/24/7 usage. But that doesn't necessarily mean you will get longer life out of a batch process water like those found on cruising boat for several reasons. The recovery rate on an industrial continually operated RO Membrane is 7%. On batch process water makers it can be as high as 25%. The truth is a cruising boat water maker won't wear the membrane out from use or some maximum treated gallonage, but most likely from poor maintenance and care.

We give a 3 year full replacement warranty on our SM30-2540 Dow Filmtec RO Membranes and have VERY FEW warranty claims. So that should tell you that we are darn confident they will last at least 3yrs.

So what's the real life life span? I say 4-7years depending on care and inlet water source. I know there are reports of a 15yr old membrane out there working great, but if I got 6-7 yrs out of a $187 40" RO Membrane, I would smile and replace it feeling that I got my money's worth.
__________________
Rich Boren Goodbye Morro Bay...Hello La Paz, Mexico and the owner of:
Cruise RO Water High Output Water
Technautic CoolBlue Refrigeration
SV THIRD DAY is offline   Reply With Quote
Old 05-04-2014, 12:58   #4
Registered User
 
nimblemotors's Avatar

Join Date: Apr 2011
Location: Sacramento, California
Boat: Solar 40ft Cat :)
Posts: 1,557
Re: How Long Does a RO Membrane Last?

No other reports from real-world lifetimes? Or does nobody want to admit they mistreat theirs and they replace them once a year??

The reason I am asking is because I'm considering making a membrane with an integrated housing, which would be half the cost of a membrane and housing, but more expensive than a membrane to replace. This makes sense to me if they really last 3-10 years,
but would not make sense if in the real world boat use they are replaced every 1-2 years.
__________________
JackB
MiniMPPT Solar Controller
nimblemotors is offline   Reply With Quote
Old 05-04-2014, 13:11   #5
Marine Service Provider
 
SV THIRD DAY's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: La Paz, Mexico
Boat: 1978 Hudson Force 50 Ketch
Posts: 3,653
Re: How Long Does a RO Membrane Last?

At $187 for a replacement SW30-2540 40" RO membrane I view them as long term consumables that need to be replaced every 5-7 yrs. We haven't seen cruisers needing to replace their membranes in the 1-2yr range. We sell about thirty 40" membranes per month to cruisers with all brands of water makers and when I'm taking orders from people I usually get feedback that their Membranes are lasing in the 5-7 yr range.

The hard thing with an intergrated Membrane/Housing would be the ongoing replacement cost. When cruisers are on a cruising budget rather than an outfitting budget the ongoing maintenance cost is an important issue. So if a cruisers can get a SW30-2540 membrane replacement for $187 and have that membrane be available world wide, trying to sell a more expensive and proprietary membrane/housing replacement I think would be a hard sell. Unless there is some performance or ease of operation improvement.

I'm not trying to discourage you...the world thrives on improvements and new ways to do things...but one of the big things people like about our brand of water makers is that we use no pproprietary parts. People know about the $399 or $599 RO Membrane and it really pisses them off when they could have bought one for $187. We get those calls all the time.
__________________
Rich Boren Goodbye Morro Bay...Hello La Paz, Mexico and the owner of:
Cruise RO Water High Output Water
Technautic CoolBlue Refrigeration
SV THIRD DAY is offline   Reply With Quote
Old 05-04-2014, 13:32   #6
Registered User
 
Travelnik's Avatar

Join Date: Mar 2012
Location: Nanny State
Boat: 22' Westerly Nomad
Posts: 593
Re: How Long Does a RO Membrane Last?

Rich,

Do you have a RO membrane that works with the Katadyn 35/40 watermakers?
__________________
Dean - 22' Westerly Nomad - Travelnik
A 14-foot mini-cruiser is minimalist. A 19ft is comfortable, and anything much larger than a 25 borders on ostentatious.
Travelnik is offline   Reply With Quote
Old 05-04-2014, 13:43   #7
Marine Service Provider
 
SV THIRD DAY's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: La Paz, Mexico
Boat: 1978 Hudson Force 50 Ketch
Posts: 3,653
Re: How Long Does a RO Membrane Last?

Quote:
Originally Posted by Travelnik View Post
Do you have a RO membrane that works with the Katadyn 35/40 watermakers?
Unfortunately, Katadyn uses their own proprietary RO Membranes, so there isn't anything "off the shelf" that will work and you have to buy replacements from them.
__________________
Rich Boren Goodbye Morro Bay...Hello La Paz, Mexico and the owner of:
Cruise RO Water High Output Water
Technautic CoolBlue Refrigeration
SV THIRD DAY is offline   Reply With Quote
Old 05-04-2014, 14:30   #8
Registered User
 
Travelnik's Avatar

Join Date: Mar 2012
Location: Nanny State
Boat: 22' Westerly Nomad
Posts: 593
Re: How Long Does a RO Membrane Last?

That's what I thought, but it never hurts to ask.

Thanks.
__________________
Dean - 22' Westerly Nomad - Travelnik
A 14-foot mini-cruiser is minimalist. A 19ft is comfortable, and anything much larger than a 25 borders on ostentatious.
Travelnik is offline   Reply With Quote
Old 05-04-2014, 17:31   #9
Registered User
 
nimblemotors's Avatar

Join Date: Apr 2011
Location: Sacramento, California
Boat: Solar 40ft Cat :)
Posts: 1,557
Re: How Long Does a RO Membrane Last?

Rich, being able to replace just the membrane for $187 is great, but then you also have
to buy the $425 housing, Water Maker Parts

If the integrated membrane was $250, you could buy 2 of them and get 10-20 years and still come out less expensive. If you cruise for 3-5 years, one may never need to replace it. I do understand that companies tend to price their proprietary parts with huge markup. What I'm planning, one could replace the integrated unit with standard parts if desired in the future, unlike some designs where that is not possible.
__________________
JackB
MiniMPPT Solar Controller
nimblemotors is offline   Reply With Quote
Old 05-04-2014, 18:39   #10
Marine Service Provider
 
Scott Berg's Avatar

Join Date: Jul 2011
Location: Aboard
Boat: Seaton 60' Ketch
Posts: 959
Re: How Long Does a RO Membrane Last?

I've seen 12yr old membranes that were still producing at 85% of max rating... They last a kong time
__________________
Scott Berg
WAĜLSS
SV CHARDONNAY
Scott Berg is online now   Reply With Quote
Old 05-04-2014, 18:46   #11
Registered User

Join Date: Dec 2010
Location: W Carib
Boat: Wildcat 35, Hobie 33
Posts: 7,964
Re: How Long Does a RO Membrane Last?

Got about 7 years out of my DOW membrane in my Spectra Catalina 300. I think about 5 is more common, but it depends heavily on how well maintained. You could easily kill one more quickly due to poor maint/use practices.
__________________
belizesailor is offline   Reply With Quote
Old 05-04-2014, 21:12   #12
Registered User

Join Date: Jul 2008
Location: South Pacific to Alaska
Boat: Morrelli & Melvin custom 52-ft catamaran
Posts: 22
Re: How Long Does a RO Membrane Last?

[QUOTE=SV THIRD DAY;1509324]We give a 3 year full replacement warranty on our SM30-2540 Dow Filmtec RO Membranes /QUOTE]

This past week I happened to mention to Spectra HQ I bought this exact membrane 2 years ago for $187 from another US RO supplier. The comeback was in effect "Dow Filmtec rates each membranes by quality - they ship the very best units to us, and the 'crap' to the low-cost suppliers. That's why ours cost so much more."

What's the real story? As far as I can tell this membrane works just fine.

Off-topic question from NZ: Is it safe to pickle with SC-3 for a couple of weeks? Because pressures have crept up from 85-ish to 105-ish I suspect the membrane needs an acid clean anyway. I'm in a rush to ship tomorrow AM our Clark Pump for a rebuild - and don't want to wait 2 days to restock on SC-1.
__________________
WombatWhiskers is offline   Reply With Quote
Old 05-04-2014, 22:09   #13
Marine Service Provider
 
SV THIRD DAY's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: La Paz, Mexico
Boat: 1978 Hudson Force 50 Ketch
Posts: 3,653
Re: How Long Does a RO Membrane Last?

Quote:
Originally Posted by WombatWhiskers View Post
This past week I happened to mention to Spectra HQ I bought this exact membrane 2 years ago for $187 from another US RO supplier. The comeback was in effect "Dow Filmtec rates each membranes by quality - they ship the very best units to us, and the 'crap' to the low-cost suppliers. That's why ours cost so much more."

What's the real story? As far as I can tell this membrane works just fine.

Off-topic question from NZ: Is it safe to pickle with SC-3 for a couple of weeks? Because pressures have crept up from 85-ish to 105-ish I suspect the membrane needs an acid clean anyway. I'm in a rush to ship tomorrow AM our Clark Pump for a rebuild - and don't want to wait 2 days to restock on SC-1.
That's the funniest thing I've heard in weeks!

Look...what do you expect them to say when selling the Dow Filmtec SW30-2540 Membrane for $399 and word gets out you can buy the same membrane for $187? Do they tell you that they are just adding an extra $212 in for profit or come up with a cover story?

This is Dow Chemical we are talking about here, not some mom and pop company that plays favorites under the table for heaven’s sake. Dow doesn't make a grade A and B Filmtec membrane. Dow doesn’t send the pick of the litter to one company, while sending the runts to others. They make one SW30-2540 industry gold standard Membrane and most of the water maker companies buy them at the same quantity pricing. What they sell them for and what they admit to be an off the shelf part...well there is the difference.

Here is the Tech Data Sheet for the Dow Filmtec SW30-2540 Membrane

If I sound irritated...well I am.
It's one thing in my view to charge as much as the market will bear for your product, heck that's the American way. It's another thing entirely to LIE to customers and attempt to frighten them out of saving some of their cruising dollars. I'm disappointed that someone at a reputable water make company would go down this road because the internet is the great equalizer in giving clients/cruisers the necessary information to sniff out and call out vendors that would give bogus answers.


I wouldn't want to use the SC-3 cleaning solution as a long term pickling reagent personally, but for only a 2 week period, I would just do a fresh water flush at the 7 day mark and skip the pickling all together. Even with your clark pump removed for servicing, you can use any pump you have aboard to push some chlorine free fresh water through the membrane to keep the bugs from growing.
__________________
Rich Boren Goodbye Morro Bay...Hello La Paz, Mexico and the owner of:
Cruise RO Water High Output Water
Technautic CoolBlue Refrigeration
SV THIRD DAY is offline   Reply With Quote
Old 05-04-2014, 23:28   #14
Registered User

Join Date: Jul 2008
Location: South Pacific to Alaska
Boat: Morrelli & Melvin custom 52-ft catamaran
Posts: 22
Re: How Long Does a RO Membrane Last?

Quote:
Originally Posted by SV THIRD DAY View Post
If I sound irritated...well I am.
Rich - thanks heaps for your instant reply. I understand your irritation. I inquired because it didn't make sense for exactly the reasons you outlined.

Plus - it's hard to believe that Dow's process control could be so poor that there would be measurable variance in unit performance.

Bottom line - passing out such information raises ??? about the reliability of the source.

Quote:
Originally Posted by SV THIRD DAY View Post

I wouldn't want to use the SC-3 cleaning solution as a long term pickling reagent personally, but for only a 2 week period, I would just do a fresh water flush at the 7 day mark and skip the pickling all together.
I was thinking the same - then realized maybe I should be doing an acid clean anyway. If true, then the pickling for 2 weeks is a "free lunch".

From my Spectra log:
Membrane is at 625 hours since new. Our 52-ft catamaran system is unusual because Spectra is on wingdeck about 1 meter above DWL. The seawater supply is pressurized by our seachest pump (feeding the genset) at typical flow rates of 34 LPM.

I'm attaching samples from our log of performance measured only when VDC >= 28V. Note how the panel pressure has ramped up while production fell off.

If you look at 11/3/2012 note that pressure and production both down because we are powering - no seachest pump.

What are your thoughts on performance, whether membrane would benefit from an acid SC-3 clean?
__________________

__________________
WombatWhiskers is offline   Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
How long does Dyneema standing rigging last? david samuelson Deck hardware: Rigging, Sails & Hoisting 2 26-10-2013 05:57
At Last . . . at Long, Long Last . . . ChrisClipper Meets & Greets 16 21-09-2012 07:18
How long does your chain last? Ram Anchoring & Mooring 35 05-04-2009 14:53
how long does diesel last limmer Engines and Propulsion Systems 7 16-02-2009 22:56
How long does a pickeling last? irwinsailor Provisioning: Food & Drink 5 18-08-2006 19:43



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 22:22.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.