How many years do you get out of your membranes?

[HowardR]

I built my first RO 6 years ago, and I've used it for 6 seasons. I'm going to replace its NF3-2540 membrane next season because it's only splitting off half the permeate that it did when it was new, and the new one only costs $175. I have three questions:

1. How many years do you get out of your membranes?

2. How do you know when it's time to replace them?

3. If you regularly get more than 6 years out of your membranes, how do you do it?

[maple flats]

I don't know, mine are in their 8th season and still perform like new.

[Russell Lampron]

When my RO was only had one membrane and I hammered 12,000 to 14,000 gallons of sap a year through it I couldn't take the time to properly clean it. I replaced the membrane every year and considered it a cost of doing business. Now that I've added a second membrane it's so much faster that I can take the time to properly clean it. This is the second season on the membranes and they still perform like new. I'm thinking that with proper cleaning and storage they will last for many years.

[HowardR]

When my RO was only had one membrane and I hammered 12,000 to 14,000 gallons of sap a year through it I couldn't take the time to properly clean it. I replaced the membrane every year and considered it a cost of doing business. Now that I've added a second membrane it's so much faster that I can take the time to properly clean it. This is the second season on the membranes and they still perform like new. I'm thinking that with proper cleaning and storage they will last for many years.

How often do you wash your membranes? I've been washing mine with lye water about 3-4 times per year, but I rinse them with permeate every time, just before I turn them off. Do you wash more frequently than that?

[Russell Lampron]

How often do you wash your membranes? I've been washing mine with lye water about 3-4 times per year, but I rinse them with permeate every time, just before I turn them off. Do you wash more frequently than that?

I do a soap wash after every use. I do an acid wash when the soap wash doesn't bring the flow rates back.

[HowardR]

I do a soap wash after every use. I do an acid wash when the soap wash doesn't bring the flow rates back.

I've never done an acid wash! Maybe I don't even need to discard my membrane! I'm going to postpone putting away my membranes (in sodium metabisulfite solution) until after I've done an acid wash. Then I won't discard the bad membrane until after I try it out next year.

Thanks for the help! By the way, I found a good thread (http://mapletrader.com/community/showthread.php?34091-Acid-wash-on-homemade-RO) about doing acid washes.

[Sunnyacres]

Not trying to hijack the thread but how long should a wash take. This is our first year with a CDL hobby 250 and the manual says it will shut off when the wash is done but has not happened yet.

[Russell Lampron]

Not trying to hijack the thread but how long should a wash take. This is our first year with a CDL hobby 250 and the manual says it will shut off when the wash is done but has not happened yet.

My Lapierre Turbo 250 heats the water while it's washing and shuts off at 43*C. Does your CDL heat the water while it's washing or do you have to heat it?

[blissville maples]

Membrane's will last several years of treated well, rinse and clean at appropriate intervals. Try not leave sugar sitting in membrane for days on end, always rinse asap.

However they are fairly cheap for the bigger producer it makes sense to replace every few years. Although I was impressed by d and g cleaning service. They test and give you a life percentage and a full readout of the performance of the membrane.

[Russell Lampron]

You should be flushing the sugar out of your membranes after every use. Concentrate with permeate until you get a 0% sugar reading on your hydrometer or refractometer. It usually takes from 5 to 10 minutes and doesn't add enough extra boiling time to worry about it. You are washing a lot of potential syrup down the drain if you don't do it.

As far as professional cleaning goes, I don't have it done. The last time I checked the price was $150 to clean a 4" membrane. A new 4" membrane is a little over $200 from MES. I can see where the cost would be justified for an 8" membrane especially if it was purchased from someone like Lapierre.