RO System help

[brew703]

Ran my system yesterday. Here's some info:
Water temp: 82 degrees
PSI: 70
2.5 gallons of RO Water to 4 gallons waste water
Took approx 30 minutes to gather
TDS Faucet: 194
TDS RO: 11
RO rejection rate: 94.33%

I think my water temp is playing a part in the rejection rate. Kinda disappointed but appears to be normal. I'll recheck when it cools off down here.

 

[Buckeye_Hydro]

With your recovery cranked up so high (2.5/(2.5+4))=38%, you should expect rejection lower than factory spec.

If rejection is critical to you, I'd lower your recovery (i.e., use a flow restrictor that allows more concentrate flow). If you're using a Filmtec membrane, remember those membranes are spec'ed at 15% recovery. Based on our test data I'd expect you'd see about a 1% improvement in rejection if you went to 15% recovery.

About half of the time we get customers calling in with rejection rate issues, the root of the problem ends up being erroneous TDS readings: TDS creep not being accounted for, dirty sample containers, taking readings after a pressure tank, etc, etc.

Russ

 

[brew703]

With your recovery cranked up so high (2.5/(2.5+4))=38%, you should expect rejection lower than factory spec.

If rejection is critical to you, I'd lower your recovery (i.e., use a flow restrictor that allows more concentrate flow). If you're using a Filmtec membrane, remember those membranes are spec'ed at 15% recovery. Based on our test data I'd expect you'd see about a 1% improvement in rejection if you went to 15% recovery.

About half of the time we get customers calling in with rejection rate issues, the root of the problem ends up being erroneous TDS readings: TDS creep not being accounted for, dirty sample containers, taking readings after a pressure tank, etc, etc.

Russ

Thanks for the info. Rejection isn't that critical as long as my system is doing it's job. I am using a Filmtec 75 GPD membrane with a 550mL flow restrictor.
I gathered some brewing water yesterday and the rejection rate was right at 95%.
And it could also be an erroneous TDS reading. I'm using an inexpensive meter which i assume is accurate. But it's been consistent since I got the system & meter so that leads me to believe it's accurate.

 

[Buckeye_Hydro]

The 550 flow restrictor on your high pressure (20 psi over spec) warm (5 degrees F over spec) feedwater is what is over-restricting the concentrate and skewing the recovery.

 

[bumstigedy]

Is there a unit I can hookup to my garden hose faucet outside?

 

[Buckeye_Hydro]

Nearly any RO system can be hooked up so that it it fed from a hose bib. You can use a hose bib slipper, and a hose bib adapter to attach the feedwater line to the hose bib.

Because much of the residential scale systems are plastic on one sort or another, you don't want the system in the sun.

Russ

 

[brew703]

The 550 flow restrictor on your high pressure (20 psi over spec) warm (5 degrees F over spec) feedwater is what is over-restricting the concentrate and skewing the recovery.

If I replace the flow restrictor with another, whichever you recommend, would i expect a 1% increase as you noted earlier? If so, would that really make a difference in the quality of water?

You mention 20psi over spec, are you referring to the 70 psi i mentioned in a previous post? Same with the temp? The temps this past weekend, when i gathered the water was around 45 degrees. I didn't think to check the water temp but if i had to guess it would have been in the 60 degree range. And the rejection rate was maybe 1% better than the last time i checked it.

 

[Buckeye_Hydro]

Yes - if you use a flow restrictor that gets you closer to a 20% recovery, your rejection would improve a bit. Is that a big deal in your case? Maybe not - but you would know better than I. I don't think that is going to change any of your calculations.

Yes - your membrane is spec'ed at 50 psi and 77F. You mentioned having have higher pressure, and higher temperature.

Colder water will yield higher rejection, BTW.

Russ

 

[brew703]

Yes - if you use a flow restrictor that gets you closer to a 20% recovery, your rejection would improve a bit. Is that a big deal in your case? Maybe not - but you would know better than I. I don't think that is going to change any of your calculations.

Yes - your membrane is spec'ed at 50 psi and 77F. You mentioned having have higher pressure, and higher temperature.

Colder water will yield higher rejection, BTW.

Russ

I did read about the specs someplace. Didn't really think about water temp effecting rejection rate and I figured 70PSI would be ok.

With the cooler temps this past weekend, I figured rejection would be higher. Winter temps usually stay in the 40's with an occasional dip below that. Summer it's bad-- 80+ degree water temp so i figured rejection would suffer some.
I may try a different flow restrictor and see how that works out. Then again, I'm no expert but I don't see a 1% increase making a noticeable difference in water quality.

Guess I just have to accept what it is and roll with it. Thanks for the info.

 

[bumstigedy]

Nearly any RO system can be hooked up so that it it fed from a hose bib. You can use a hose bib slipper, and a hose bib adapter to attach the feedwater line to the hose bib.



Because much of the residential scale systems are plastic on one sort or another, you don't want the system in the sun.



Russ

Thanks. One additional question: Would occasional use of an to system be a problem? I would plan to store it in my garage and hook it up outside once a month when I brew.

 

[bumstigedy]

Nearly any RO system can be hooked up so that it it fed from a hose bib. You can use a hose bib slipper, and a hose bib adapter to attach the feedwater line to the hose bib.



Because much of the residential scale systems are plastic on one sort or another, you don't want the system in the sun.



Russ

Thanks. One additional question: Would occasional use of an to system be a problem? I would plan to store it in my garage and hook it up outside once a month when I brew.

 

[bumstigedy]

Thanks for the reply about the outside hookup. One additional question: Would occasional use of an to system be a problem? I would plan to store it in my garage and hook it up outside once a month when I brew.

 

[Buckeye_Hydro]

Any RO system should be used at least once per week.

Russ

 

[whovous]

Any RO system should be used at least once per week.

Russ

Why? My system is always connected. What happens when I don't use it? And how much use is enough use in a week?

 

[Buckeye_Hydro]

Membrane manufacturer's recommendation. Any membrane not used for a week+ should be removed and treated with a preservative. That's the textbook answer. Biofouling is the issue. Remember your membrane is soaking in dechlorinated water - there's no disinfectant left in the water by the time it reaches the membrane.

Russ

 

[millstone]

So every time I go on vacation I would have to treat it when I return? Also what preservative is used?
thanks

 

[whovous]

Membrane manufacturer's recommendation. Any membrane not used for a week+ should be removed and treated with a preservative. That's the textbook answer. Biofouling is the issue. Remember your membrane is soaking in dechlorinated water - there's no disinfectant left in the water by the time it reaches the membrane.

Russ

Adding to Millstone's questions: Is there an easy way to test my water to find out if bio-fouling has indeed taken place? And just where do we find this "membrane" amongst all the cannisters under my sink?

 

[Buckeye_Hydro]

So every time I go on vacation I would have to treat it when I return? Also what preservative is used?

The textbook answer is "yes." But in practice 9 gazillion people have not done that and have been ok. You lives your life, you takes your chances

There are commercially available preservatives. Or you can use a sodium metabisulfite as well. Many brewers seem to have that handy.

 

[Buckeye_Hydro]

Is there an easy way to test my water to find out if bio-fouling has indeed taken place?

Easiest way to detect it is to smell the end of the membrane inside the housing. Biofouled membranes typically stink.

 

[Buckeye_Hydro]

And just where do we find this "membrane" amongst all the cannisters under my sink?

In this picture the membrane is INSIDE the larger of the two horizontal housings above the bracket. Feel free to email us a pic of your system if you're not certain of what is inside any of your housings - [email protected]

Russ

 

[whovous]

Wow, thanks for all these responses. More questions:
Should the water also smell?
My PO water is exclusively for beer. It is always boiled. Does this mean I do not need to worry about this.
My system looks much like yours, but with one more vertical housing.

 

[Buckeye_Hydro]

The water coming out of the RO may or may not smell.

A fouled membrane won't work as you expect it to - it can't because it is clogged/plugged with organic nastiness. So you want to avoid a fouled membrane, regardless of what you do with the water after it comes out of the membrane.

The vertical housings contain "prefilters." A prefilter is any filter that touches the water before it reaches the RO membrane. Common prefilters include sediment filters and carbon blocks. As a general rule of thumb, one sediment filter and one carbon block should be your default prefilter configuration. Add additional if needed as dictated by your water quality issues.

Russ

 

[whovous]

I may finally be running out of questions!

Do I simply unscrew the end of the cannister and add some SMB? How much?

 

[Buckeye_Hydro]

Nope. Pull the membrane out, and submerge it in a solution of RO water and SMB. Solution should be 1% SMB by weight. After soaking it submerged for a bit, pull the membrane out and immediately seal it in a plastic bag.

 

[passedpawn]

Rec'd my RO system. Came from Bulk Reef Supply, 75 GPD 4 stage.
Set it up, checked for leaks and all is good. Ran for an hour per instructions.
70psi
Tap TDS= 192
RO TDS= 012

Does this seem correct?

I'll bet it looks a lot like this one (it's for my fish tank). Same one you got, but with the TDS and pressure meter. It replaced a Kent unit I had for 20 yrs. So far it's working as expected. BTW, I get zero on the TDS output. I feed this from a water softener, so that might help.

 

[schematix]

If you have a permanently plumbed and mounted system you can get crafty with a few solenoids and a timer to perform an automatic system purge.

 

[whovous]

If you have a permanently plumbed and mounted system you can get crafty with a few solenoids and a timer to perform an automatic system purge.

Where can I find a write-up on this?

 

[MaryB]

Buckeye Hydro is great! I have a 100GPD membrane system from them and with my ice cold input water(~45 degrees right now) I see 40GPD output. Neighbors drink coffee so I am filtering water for them and for beer, plus I filter for cooking now. My water has a stupid high amount of sulfates and it stinks! The filtered output is tasty and clean!

 

[augiedoggy]

I'll bet it looks a lot like this one (it's for my fish tank). Same one you got, but with the TDS and pressure meter. It replaced a Kent unit I had for 20 yrs. So far it's working as expected. BTW, I get zero on the TDS output. I feed this from a water softener, so that might help.

View attachment 551087

looks a lot like my reef tank RO setup. with 1.5 gallons of evap a day mine sees plenty of use.
If I was concerned my mebrane might be bad I would replace it... This is what they look like. I believe theres only a few manufacturers of these despite many many brands. most use dow filmtec I believe as the membrane material.
https://www.ebay.com/itm/Best-Quality-RO-Reverse-Osmosis-Membrane-Filter-50-75-100-GPD-TFC-TW30-1812-2012/272507899287?hash=item3f72bc8d97:m:mruxyIXxazI8E6rhzMD9Kvg this one has a diagram explaining what filter does what.

https://www.ebay.com/itm/24-36-50-7...hash=item3add6f7001:m:mvIrAhmC96uVgBepecb6Hew

 

[Buckeye_Hydro]

I'll bet it looks a lot like this one (it's for my fish tank). Same one you got, but with the TDS and pressure meter. It replaced a Kent unit I had for 20 yrs. So far it's working as expected. BTW, I get zero on the TDS output. I feed this from a water softener, so that might help.

View attachment 551087

This is an RODI system - it is the DI stage that brings the RO water TDS down to 0 ppm. Probably overkill for brewing.

Russ