Are All RO Membranes Created Equal?

[-=Efrain=-]

I am in the market for a RO Membrane and I have noticed that most of them are made by Membranes Inc. But I have also noticed that the prices vary from 26.00 - 55.00 for the same 100 gpd membrane so my question is are they all created equal? All so I noticed that you can purchase a 18, 24, 36, 50, 75, 100 and 175 GPD membranes but how do they control the rate? Is it with less filament?

 

[taylor t]

No, they are not created equally. They have different rejection rates, and they also need to be matched up with the flow restrictor sized accordingly. IE: if you have a 60 GPD unit, you must use a 60 GPD membrane, unless you change the membrane AND change the flow restrictor to match each other. Most likely, a more expensive membrane has a higher rejection rate, but not always... Hope this made sense.

 

[-=Efrain=-]

Taylor,

If my restrictor is a 60 gpd but I purchased a 100 gpd membrane that just means I will only get 60 gpd correct? Or will the membrane not work at all which doesn't make sense but you never know in this hobby..

 

[Vinny Kreyling]

The membrane & restrictor have to be matched.

 

[jwblocal701]

I have heard spectrapure ones are great

 

[goat585]

Taylor,

If my restrictor is a 60 gpd but I purchased a 100 gpd membrane that just means I will only get 60 gpd correct? Or will the membrane not work at all which doesn't make sense but you never know in this hobby..

It may not work at all or will be even less efficient. If you have a 60 gpd membrane you should use a flow restrictor designed for a 60 gpd membrane.

Dow Filmac membranes are typically considered the top of the line membranes in the industry. 75 gpd membranes are typically the most efficient as far as product water to waste water. I think this membrane is most commonly used.

 

[mtrcyclefish]

The flow restrictors are pretty cheap. If you want to put in a different membrane it's an easy upgrade.

 

[taylor t]

The flow restrictors are pretty cheap. If you want to put in a different membrane it's an easy upgrade.

+1. Usually easy to do.

These are the ones I use.
http://www.rosystems.com/mm5/merchant.mvc?Screen=PROD&Store_Code=RSI&Product_Code=TW30-1812-100

I think osmotics are a better membrane for a higher rejection, (higher quality product water) but filmtec is cheaper, and higher/faster output, which is what I am interested in, being on a well.

 

[skunkmere]

i always get the filmtec, i think the 75gpd has the best rejection rate. it all depends on your feed water tds. whats your tds?

 

[dja1980]

I have heard spectrapure ones are great

+1... but you DEFINITELY want the SpectraSELECT. The difference between 96% & 98+% rejection is HUGE...

http://www.reefcentral.com/forums/showthread.php?t=895507

PS... you can get a SpectraSELECT for $45 using the RC Customer Appreciation Page...

http://www.spectrapure.com/email/customer-appreciation.html

 

[Buckeye Hydro]

All membranes are not alike. Here's some info to help you compare some of the more popular membranes: