Poorly performing RO system.

[Octocat]

Hello-

I recently setup my BRS 7-stage RODI system, and I'm not getting the results I expected from the RO portion. Water pressure is 55 psi, input water tds is 600 and temperature is 84 f. Output water has been between 25-30 tds on the inline meter and my handheld checker. By comparison my last unit was producing water in the 10-15 tds range. I tried to remove and reinstall the RO filter to reseat it but no change in tds.

I wanted to get this tank setup and cycling so I made about 100 gallons and the DI part was still able to get tds down to 0. However, I burned through nearly 1/3 of my anion resin doing so (less of the others).

So, I need to get the tds down in the RO water. Given my last unit was performing better, I think the RO filter is defective and needs to be replaced- preferably by one with a better rejection rate than the 96-98% of the BRS 100 GPD filter. Does this make sense or would I be better of trying something else first? I read that RO filters perform better at higher pressure. Is it possible a boost pump would make a significant difference to rejection rate?

 

[JoshH]

I'm a little rusty with BRS' system stages does the 7 stage system have dual RO membranes? If so I would absolutely say pressure is a huge concern here and a booster pump is needed.

 

[Octocat]

I should have mentioned, it is the 100 GPD unit with a single membrane. BRS states the minimum water pressure is 50 psi.

 

[JoshH]

A booster pump would still certainly help with your rejection rate, how much that I'm not entirely sure. 55PSI is definitely at the lower end of the spectrum for pressure, not soo bad for a 75 GPD membrane but when you start stepping into the larger ones it can be an issue. It is worth mentioning you do have rather high incoming TDS and the 100 GPD membrane is barely operating outside of its specifications so I wouldn't say it's shot by any means...

 

[Opus]

Well, your unit is operating within spec or at least close to it. BRS has great customer service so they might replace the membrane. A booster pump would help but not sure enough to warrant the cost.

You may want to look at getting a spectrapure 99% rejection rate membrane. They are rated at 90gpd so close to what you have. I have one and my water is around 450tds and my tds after the membrane is 3 to 4.

 

[JoshH]

You may want to look at getting a spectrapure 99% rejection rate membrane. They are rated at 90gpd so close to what you have. I have one and my water is around 450tds and my tds after the membrane is 3 to 4.

++++++ 1

Love my Spectrapure Plus membranes, though they do not claim the 99% anymore which is a little concerning they certainly still perform as they did before around the 99+% range

I run dual Spectrapure Select Plus 90GPD membranes on my system and they take my 240ish TDS down to 0-1 running on around 85ish PSI.

 

[Opus]

++++++ 1

Love my Spectrapure Plus membranes, though they do not claim the 99% anymore which is a little concerning they certainly still perform as they did before around the 99+% range

I run dual Spectrapure Select Plus 90GPD membranes on my system and they take my 240ish TDS down to 0-1 running on around 85ish PSI.

I didn't know they had changed it to 98%. Checking their site I see they now say that 98% is the min with 99% being the norm.

 

[JoshH]

I didn't know they had changed it to 98%. Checking their site I see they now say that 98% is the min with 99% being the norm.

That's correct, they changed that little bit when they updated there website. I noticed it and sent them an email but I never got a response to it. I can say they still perform fantastic in that 99+ range, they just don't guarantee it anymore it seems.

 

[Octocat]

Well, your unit is operating within spec or at least close to it. BRS has great customer service so they might replace the membrane. A booster pump would help but not sure enough to warrant the cost.

You may want to look at getting a spectrapure 99% rejection rate membrane. They are rated at 90gpd so close to what you have. I have one and my water is around 450tds and my tds after the membrane is 3 to 4.

Yeah, calling the unit defective was a probably a poor choice of words. More like not meeting expectations based on previous experience. I should have done more research before purchasing a RODI unit. The BRS 75 GPD unit would have been a better choice. I'll look at the spectrapure membrane you guys mentioned.

 

[JoshH]

Yeah, calling the unit defective was a probably a poor choice of words. More like not meeting expectations based on previous experience. I should have done more research before purchasing a RODI unit. The BRS 75 GPD unit would have been a better choice. I'll look at the spectrapure membrane you guys mentioned.

The great part about RODI units is the filters aren't crazy expensive to swap out if you want to try something else. And as long as the membranes stay moist you can store them for quite some time.

The downside to RODI filters is everyone truly had a unique situation when it comes to water quality/pressure feeding there systems which makes it very difficult to find a one size fits all system.

 

[vetteguy53081]

Mine fills quickly to the point, you gotta keep a close eye on the darn thing.
Assure none of cartridges are installed backwards and valve is wide open from membrane through the system

 

[Water Dog]

If you get the Spectrapure membrane, be sure to get the proper capillary flow restrictor for it and trim it yourself to get the proper 4:1 waste to product water ratio. That will ensure that you’re running the membrane at maximum efficiency. Spectrapure is actually located in Tempe, AZ so you should swing by there location as they are local to you.

 

[Octocat]

I wanted to provide an update for anyone who stumbles onto this thread.

First, I did end up visiting Spectrapure. But, not to buy a ro membrane! Rather, I picked up their litermeter pump for my ATO setup. Really helpful people, and based off the reviews, high quality products as well.

As for the ro setup, the membrane BRS unit eventually started to produce great results. After making about 100 more gallons (after the original post), output water was down to 10 tds. Better than 98% rejection rate! Recently, the input water dropped.to ~300 tds and I am seeing 4 tds in output water!

At this point, the color of second and third di beds indicates they are spent. But, the output water remains 0 tds. I've probably run 350-400 gallons through it.