Questions about RO membranes

[leafyseadragon]

Pretty soon I will replace the membrane in my RO filter. I make roughly 15-20 gallons of water per WEEK, so I assume a 35 GPD membrane will more than suit my needs.

What I would like to know is what else would I be getting if I bought a 75 GPD membrane instead. Could I use it twice as long before replacing it? Will it fill up my 5 gallon jug twice as fast? Does it create less waste water?

 

[Steven Pro]

It will fill up your water vessel quicker, but it will not create less waste water.

 

[MT79]

You should not use a membrane w/ a different gpd level than what the unit originally came with unless you change the flow restrictor in the unit as well.

Could I use it twice as long before replacing it?

Probably not.

? Does it create less waste water?

No.

 

[Ziggy953]

I agree with Mike. Stick with what you started out with...your RO/DI system was designed for a flow output of 35gpd and that is the membrane you need.

 

[Steven Pro]

Replacing the flow restrictor is extremely cheap and easy and in most cases needs to be done anyhow. The first RO units I sold were 30 gpd models from SpectrraPure. A few years after they were sold, it was time to replace the membranes. Well, the membranes had improved to the point where they were 35 gpd units and need new flow restrictors too. That was a few years ago and now those same models use 40 gpd membranes and will need new flow restrictors when they are replaced again.