RO Membrane info

[Mark_C]

My system crapped out and, after complete disassembly, all is good, so the membrane seems the suspect.

I have a Spectrapure MFM0090 standard membrane in there now.
If I replace it with same, it will take a few days to a week to receive, in which case I will end up buying water.
But...
Amazon has loads of them for next day Prime delivery, but they don't have Spectrapure.

Are these thing generically sized?

 

[motortrendz]

I'm 99% sure if you match the gallon per day number they should be the same.

 

[iTzJu]

I'm 99% sure if you match the gallon per day number they should be the same.

I'm pretty sure as well. Amazon and eBay has a ton of membranes available, I usually stick with Filmtec DOW membranes but am using one of the "cheaper" ones on a secondary membrane I use with the waste water from the first, seeing how well they hold up.

I will still stick with Filmtec ones for the main membranebut for the secondary one, $15 compared to $40 is a big savings.

 

[Mrx7899x]

I'm sure they are fine when it comes to drinking water and things like that they have government standards that they have to meet.

 

[jgraz]

And as long as you monitoring your TDS coming out of membrane you will have a good idea how its performing.

 

[Hallowhead]

What I got off amazon but they should be generic sizes.

 

[Mark_C]

READ THIS FOR A BIT OF MEMBRANE FYI

OK, did a bunch of research today.
Here's what I learned via GE, Dow, two major fish retailer employees, and one long term hobbiest.

Membranes are membranes.
The difference is in effectiveness and daily production (gallons per day). We should be most concerned about the efficiency bit.
Household membranes for drinking water (Dow, GE, etc...) are rated at 95% efficient by government standard, they remove 95% of TDS (total dissolved solids) as well as spores and metals.
Aquarium membranes can be less effective at 90% (the cheap ones) or more effective at up to 99% (like Spectrapure).
Many aquarium membranes are manufactured by the same companies that make the household membranes, and of course, the aquarium membranes are priced higher as a hobby niche item.

If the water coming into your house is 1-150/200 TDS, a 95% household membrane is fine, they're pretty much standard size.
If your water coming in has a TDS of 250+, you're probably safer with an aquarium specific 99% membrane.
If you're over 400 TDS, you definitely need the aquarium specific 99% membrane.

I'm running 120-130 TDS in.
I went to the big orange home improvement store and picked up a GE RO membrane for drinking water, priced at $39.
Was wary on installation and use, but it fit perfectly, had a good output, and TDS in is between 128-130, TDS out is 0.

 

[radiata]

Mark_C...

With standard sized membranes, I'm inclined to believe that "one size fits all". I haven't looked, but I'd personally defer to any BRS preferred brands. My only caveat is that you perform the necessary cleansing of the membrane (running it for X* gallons and then tossing out the water.) I once had a serious problem that I could only attribute it to my not having performed the necessary cleansing. (Cleansing sounds like some sort of religious ritual, but it really doesn't require the presence of a priest.)

* Sorry, I don't recollect the value of X.