R O Membrane Question

We will be moving into a new to us home in a few weeks and I have a question about R.O. membranes. Are they manufacturer specific or are they gallons per day specific?

 

Anyone?

 

I don't really understand the question. What do you mean by manufacturer specific? Membranes generally have a gpd rating. There are only a couple of manufacturers. Spectrapure test each of their membranes and only sells those with a high rejection rate
With spectrapure being local to you, that would be my first choice, for that matter they are my first choice even if not local

 

By manufacturer specific I mean the manufacturer of the entire R.O unit. Do I have to buy membranes made by the same manufacturer?

 

Most are interchangeable, I think the exceptions being larger commercial units. But yes if you have a airwaterice unit a brs or spectrapure membrane will work in it and visa versa. If you want to change the gpd rating then you need to change a flow restrictor to match the membrane you want to use, usually sells for under $5

 

How often should you change an RO membrane? Is it good for a certain number of gallons or are we best to look for a specific time period?

 

I think if you change your prefilters on a regular basis, like every 6 months, more often under heavy use or with bad source water, ro membranes will last for years. They can't dry out though so if you had one in storage it would need to be replaced.

 

+ 1 to everything Rick said. A TDS meter will tell you the condition of your filter media. The RO membrane should last several years if you keep the carbon prefilter changed regularly. When the carbon gets exhausted, it lets chlorine pass into the RO membrane shortening the life.

 

Most membranes are the same size with certain exceptions including units by Whirlpool, Sears, Watts Premier and some others.
By far the most popular brand is Dow Filmtec which comes in 15 to 100 GPD sizes and all are interchangable. GE Water also makes membranes tha tfit in the same housings but the ratings are slightly different as in a 100 GPD GE is identical to a 75 GPD Dow.

The life of a membrane depends on how well you take care of it. By that I mean cheap ebay sediment and carbon filters will lead to a short membrane life while bette rquality filters will greatly extend its life. You also must replace the sediment and carbon filters every 6 months to a year and sisinfect the housings to keep them clean and free of viruses and bacteria. It is also highly recommended you use softened water for a RO or RO/DI system. A well taken care of membrane can easily last 5-10 years of heavy use if you follow those recommendations while most ebay quality systems ge tabout 18-24 months on average of of a membrane.