View Full Version : How do you know when a membrane has gone bad?

03/22/2013, 02:41 PM
I know the main way to tell is by the rejection ratio. Any other way?

Buckeye Hydro
03/22/2013, 04:18 PM
The two thisgs you might see in a membrane gone bad are:
1) rejection rate worse thatn you'd like, and/or
2) reduced (slowed) production

The production is a little tricky because you have to normalize it (account for) any changes in water temperature and water pressure. The easiest thing to do is to use the calculator on our home page - plug in your temperature and pressure and see how many gallons your membrane should be producing per day given those conditions.


03/25/2013, 03:28 PM
Do you have a recommendation for a new membrane that puts out between 75gpd and 100 gpd? Also which restrictor would you go with? Thanks

Buckeye Hydro
03/25/2013, 03:48 PM
BFS-52 75 gpd Filmtec RO membrane (or better yet, BFS-5147 NEW!! MAXR RO Membrane)with BFS-217 Capillary flow restrictor, pre-trimmed for 75 gpd


BFS-53 100 gpd Filmtec RO membrane with BFS-218 Capillary flow restrictor, pre-trimmed for 100 gpd

The rejection rates vary:
MAXR: 98% or more
Regular 75 gpd: 96 to 98%
100 gpd: 90%


03/25/2013, 05:57 PM
What's the good to waste water ratio on the new MAXR membrane?

Sent from my Samsung Galaxy S III

Buckeye Hydro
03/26/2013, 07:50 PM
Like any membrane, you can set that ratio to whatever you choose by changing the water temperature, water pressure, and/or your flow restrictor.

That ratio isn't "set" by the membrane...


03/26/2013, 09:29 PM
Let me be a little more specific with my good to bad water ratio question.

With that MAXR membrane with BFS-217 Capillary flow restrictor, pre-trimmed for 75 gpd and with 70 degree input water with 60psi, what type of good to bad water ratio should I expect?


Buckeye Hydro
03/27/2013, 02:48 AM
~4:1 with that restrictor.