Are all membranes created equal?

[Bruce Spiegelman]

Are these equal to the BRS or Dow brands sold on BRS for 3x the price?

https://www.amazon.com/Alberts-Filter-Replacement-Residential-Purification/dp/B07BPSFLNW/ref=sr_1_4?gclid=CjwKCAiAzuPuBRAIEiwAkkmOSGFud-0nBhcnHaDUK86GqM5rwnEpHcgO-8ze1I1AKeqF60OuDp72RRoCxusQAvD_BwE&hvadid=323597311129&hvdev=c&hvlocphy=1013763&hvnetw=g&hvpos=1t1&hvqmt=b&hvrand=12277455900581215560&hvtargid=aud-840076997981%3Akwd-517960243617&hydadcr=27638_9997627&keywords=150+ro+membrane&qid=1574527094&sr=8-4

 

[Coral reefer]

I would go with multiple smaller membranes instead.

 

[Bruce Spiegelman]

I would go with multiple smaller membranes instead.

Huh? I have two membrane housings. So you'd do two 75gpd instead of 150 gpd's? Why?

 

[Bruce Spiegelman]

And does brand matter?

 

[Coral reefer]

Honestly don’t know. It says 97% rejection. If that’s true should be ok.

 

[sfsuphysics]

I thought they were all made by Dow, just rebranded under different names.

 

[Wlachnit]

I thought they were all made by Dow, just rebranded under different names.

I've always thought as well.

 

[yellojello]

I’m using the spectrapure 90 gpd membranes, supposed to have really good rejection rate. Haven’t done any calculations on actual use but technically should make the DI last longer. I’m sure those cheap ones would be fine too though.

In San Jose, I remember invoking tds was mid to high 200’s. Recently it’s been under 200. I guess it depends on if we have a drought season or not?

 

[Coral reefer]

Your supply can come from different places at different times too.

 

[Macroman]

Older RO and commercial RO systems use different materials. They normally are higher pressure than city water. The sediment filters and the carbon filters do not remove the larger ion complexes. Normally the hard water is softened before it enters the RO membranes. The well water in the peninsula and SJ is very hard. The Hetch Hetchy water is relatively soft. In Mtview the switching between Sierra water and wells would play havoc on the softeners setups.

 

[rygh]

Be warned that not all membranes fit all housings.
I have an old 75 GPD one from BRS.
It clogged and was urgent so I bought a 100 GPD one from local AC. It did not fit right.

 

[Coral reefer]

Be warned that not all membranes fit all housings.
I have an old 75 GPD one from BRS.
It clogged and was urgent so I bought a 100 GPD one from local AC. It did not fit right.

I’ve never encountered this before. And have used those membranes in housings from brs. Are you sure you pushed it all the way in?

 

[rygh]

I’ve never encountered this before. And have used those membranes in housings from brs. Are you sure you pushed it all the way in?

That was the problem - it would not go in. Too tight.
It jammed when it hit the tape over the rubber gasket.

Maybe it was defective and had swelled up.

 

[Flagg37]

Be warned that not all membranes fit all housings.
I have an old 75 GPD one from BRS.
It clogged and was urgent so I bought a 100 GPD one from local AC. It did not fit right.

I was a little concerned about this when I bought my last one but when I received it they looked identical. Either I lucked out or they are a standard size.