What am I really saving by using two RO membranes versus one? | BRStv Investigates

[dragon99]

Looks like you are getting 99% rejection, thats amazing. I only get 96.5-97% rejection.

Are you using membrane from BRS?

I bought the water saver kit from BRS, but the first membrane is a Dow membrane I bought somewhere else. I calculated it @ 98.8% rejection which is amazing I agree. I have great water pressure though, 85psi in front of the membrane with no booster.

 

[Rogue Snail]

How high can TDS be and if the display reads 1 TDS could it be 1001 but only showing the 1 since it has only 3 digits?

 

[tigé21v]

How high can TDS be and if the display reads 1 TDS could it be 1001 but only showing the 1 since it has only 3 digits?

;Jawdrop

 

[tigé21v]

Does anyone know if the DI resin's life is affected by the flow rate through the resin? If you double the flow through the resin, does it reduce total gallons the resin can process?

 

[shuford1]

Best thing I ever did

 

[Millhugh718]

i love these investigation, just ordered a bunch more of BRS replacement accessories for my 150 GPD

 

[Millhugh718]

@shuford1 very neat man

 

[shuford1]

@shuford1 very neat man

Thank you

 

[JamesP]

Another amazing video from brs! So as an engineer I like to tinker and I did something cool to my system to reduce di consumption substantially and to prolong the life of my membranes.

First, an auto flush kit is great for membrane life and I recommend one to everyone who can. Second, and this is where the tinkering comes in, I installed a timer used for HVAC and a NC solenoid that will dump the first 60 seconds of product water down the drain automatically.

So when I open my product water spout it starts the flush cycle which lasts about 20 seconds while simultaneously starting the dump cycle that lasts about 60 seconds. My system is plumbed straight to my ato (with lots of failsafes) but this causes short cycling and i was burning through di resin like crazy. This fixed it and im loving it. Another option would have been to only have the ato on for a few hours a day to avoid short cycling, but would have made my parameters swing much more. I like this solution a lot better.

 

[MARK N]

In what configuration does the water saver 150 come in when purchased assembled form BRS?
(Series or parallel)

 

[Frop]

I did the 150gpd upgrade to my BRS RO unit and within a few short months the second membrane was shot, it wouldn't produce anything below 20 TDs. My tap water TDS is around 300 and it gets 80 psi. I spoke with BRS and they recommended I not do anymore. I spoke with another RO company and they said it will work, as long as I'm okay with replacing RO membranes every few months rather than every few years. So I am now
back to a single membrane. It's a waste of money in my opinion.

My incoming TDS is 670. So I doubt your first membrane is putting more than that out into the feed of the second as what the feed of my only membrane is getting. Crazy it can go out so fast. Also I run mine at 100psi

 

[mic209]

My incoming TDS is 670. So I doubt your first membrane is putting more than that out into the feed of the second as what the feed of my only membrane is getting. Crazy it can go out so fast. Also I run mine at 100psi

Are you referring to a parallel or series dual membrane setup?

 

[mic209]

Does anyone know if the DI resin's life is affected by the flow rate through the resin? If you double the flow through the resin, does it reduce total gallons the resin can process?

I don't think it affects it at all, believe it or not there are people who run tap water straight into DI filters without any RO.

 

[JamesP]

It is the tds going into the resin that effects its usable life. This is why you run a prefilter such as an ro system in front of it. I wouldnt trust a 10 inch resin bed to remove everything in the water myself. An ro membrane can actually remove waterborne pathogens since h20 is so small at a molecular level. Can di resin do that? I really dont know.

 

[Frop]

Are you referring to a parallel or series dual membrane setup?

Im referring to the plumbing from the city to my house provides 800 TDS. The water softener actually drops that by 130. Then my single membrane drops it another 660+. DI takes the remaining 8-10.

 

[JamesP]

Im referring to the plumbing from the city to my house provides 800 TDS. The water softener actually drops that by 130. Then my single membrane drops it another 660+. DI takes the remaining 8-10.

Good grief that is high tds! The epa says the legal limit is 1000ppm for city water. My tds is 55ppm from the street which is exceptionally low. That water is going to clog your arteries lol.

 

[Frop]

Good grief that is high tds! The epa says the legal limit is 1000ppm for city water. My tds is 55ppm from the street which is exceptionally low. That water is going to clog your arteries lol.

I thought EPA was 500? lol ya we just cook with that water and use 5 gallon purified jugs for drinking. Debating purifying my own now the house we live in is 70+ years old (all we could afford in Southern California). So I think the old pipes have a lot of build up that leaches into our water. Our house plumbing is relatively new however (copper).

 

[JamesP]

I wonder if running a second sediment filter would be of use in this case. Id be curious to see the tds at each stage of the rodi system.

 

[Frop]

I wonder if running a second sediment filter would be of use in this case. Id be curious to see the tds at each stage of the rodi system.

Ya I'll check it out later (maybe tonight). I have one .5 micron sediment filter. I'll just fill up a cup of water before and after the filter and use my handheld TDS to see what the difference is.

 

[JamesP]

Ya I'll check it out later (maybe tonight). I have one .5 micron sediment filter. I'll just fill up a cup of water before and after the filter and use my handheld TDS to see what the difference is.

Frop investigates lol