RO Membrane Issue

[ostrow]

I posted this in Large Tanks, because my first question was to those who have large systems. Now, though, it is just about this:

Why am I only getting 3-6 months out of a membrane? Using Dow Filmtec 75gpd membranes. The discussion is here. I do all the obvious stuff correctly and diligently. And have done for 15 yrs. This only started three membranes ago, 18months ago (just put 4th in a couple days ago).

http://reefcentral.com/forums/showth...9#post25340169

[Rover88]

Are you on city water or well water? Do you measure your incoming TDS before any of your filters to see if it changed? Maybe the city changed something up that caused more TDS to be incoming to your lines, or something of that sort thats eating up your membrances usefulness faster.

[mcgyvr]

Call.. ask for Russ..
Do no pass Go.. Do not collect $100..
http://www.buckeyehydro.com/contact/

[alton]

My issue with changing membranes so fast was Chloramines! I could use three of the 2"x 10" Chloramine filters and they would be spent which meant my membrane wasn't going to last. Now my system contains one BRS Chloramine Monster, 4" x 20" almost 20LBS of media to fight the junk.

[Opus123]

I just checked your towns water report and they don't use Chloramines. All your water comes from Chicago and they say they only use chlorine.

Is your system 15 years old, in that the only thing you have changed is the filters/membrane/DI?

What is your tds at the tap and after the ro membrane?

[ostrow]

Originally Posted by Opus123

I just checked your towns water report and they don't use Chloramines. All your water comes from Chicago and they say they only use chlorine.

Is your system 15 years old, in that the only thing you have changed is the filters/membrane/DI?

What is your tds at the tap and after the ro membrane?

I've spoken to Russ. No real answers.

The good thing about Chicago is it's big. Right, no chloramines. Other local reefers show what I show. Over the course of a year, tds out of the tap averages about 225. Winter typically lower.

Not sure what you mean by out of the membrane. A new membrane shows 2. But my 6mo old one just before I asked on here was at 20. Dead. That's what happens every 3-6 mos for the last several membranes now.

No changes in that time to the system.

I can't imagine the cartridge housings are the issue. No leaks. No problems. The membrane cartridge I replaced for kicks a while back (maybe 4 yrs ago?).

So, 2 out of a new membrane. I replace all the pre-filters regularly, as I described. Russ said not to flush. Others said flush more. I will try no flushing for this membrane and see if that fixes the issue.

Can't figure out the problem. In the end, membranes are cheap. I can manage the $35 every 6 months I guess. But would rather not have to!

[Opus123]

Have you tested to see what your waste to good water ratio is at currently? Only thing I can think of currently is something is wrong with the flow restrictor and I'm not sure that would even hurt the membrane. Also, maybe something is wrong with the solenoid and there is back pressure on the membrane. I've read that can damage them.

[ostrow]

Hmm. Well I replaced the flow restrictor for no apparent reason about a year ago. I just assumed it was a "consumable". Maybe I will put the old one back.

How would you test that ratio? And how would I know about the solenoid?

[outy]

You need to know what incoming TDS is and outgoing before DI.

Then you can play with the restrictor and tune your system

[Opus123]

Originally Posted by outy

You need to know what incoming TDS is and outgoing before DI.

Then you can play with the restrictor and tune your system

He stated that in a previous reply. Tap averages around 225, new membrane is 2 and gets to around 20 after 6 months.

[outy]

Originally Posted by ostrow

In the end, membranes are cheap.

You might try a different brand. From a different vendor


But the only change I see is you changing your restrictor.


You can measure how long it takes to fill a cup with ro water, then your waste water to figure your actual ratio out

[Opus123]

Originally Posted by ostrow

Hmm. Well I replaced the flow restrictor for no apparent reason about a year ago. I just assumed it was a "consumable". Maybe I will put the old one back.

How would you test that ratio? And how would I know about the solenoid?

To test the ratio, take the waste line and let it fill a measurable cup for a set amount of time. Then do the same with the good water line. You then compare the 2 to get your ratio.

I'm not sure on the solenoid. Also not sure if a bad flow restrictor would hurt the membrane.

[Opus123]

Where are you getting your membranes?

[ostrow]

Originally Posted by Opus123

Where are you getting your membranes?

Unclear why that matters. I think my last order was from Air Water and Ice. They are Dow Filmtec membranes not a knockoff. 98% rejection rate. Same I've always used.

I will test the ratio but I can say that I definitely get the rated 3gph and change. 16hrs to fill my 50g reservoir

[outy]

Originally Posted by ostrow

not a knockoff.

have you ever tried one ?

I have low TDS and I use the cheapest and always get 0 before DI

[Opus123]

Just wanted to make sure you weren't going thru ebay. There are fakes on there from what I have read.

Honestly it sounds like everything is OK with your unit. My final thought is a CO2 issue, though that is usually a well water issue plus I would think others in your area would have the same issue.

[ostrow]

Originally Posted by Opus123

Just wanted to make sure you weren't going thru ebay. There are fakes on there from what I have read.

Honestly it sounds like everything is OK with your unit. My final thought is a CO2 issue, though that is usually a well water issue plus I would think others in your area would have the same issue.

Yeah. But nobody else here has this problem. So very, very strange.

[outy]

Originally Posted by Opus123

There are fakes on there from what I have read.

.

I'm using their cheapest membranes with excellent results, but I don't have the challenge OP does. my TDS is the lowest in the nation. BUT if those cheapys were junk I would not be getting zero pre DI

[Opus123]

What micron size do you use on your prefilters? My water is over 400 tds and get 4 or 5 years out of my membranes. I usually go with 1 or .5 micron my sediment filters.

[outy]

Mine are .10 I have had a membrane last 10 years before and changed it just because.

never seen anything but zero pre DI in 25 years

Right now I run 3 membranes as water savers in series, in a few years ill move from 75gpd to 100 god ebay cheapies as I don't need much to get to zero.

I will say tuning my restrictor was a key turning point in production and water saving.

[Opus123]

Where do you get .1 sediment filters. Best I've ever seen are .2 and they are around $30 each. I really don't treat my RO unit like I should. I'm lazy and will go a year to 2 years between prefilter changes but still get 4 or 5 years out of a membrane. I don't worry about the water saving, our water is cheap.

[ostrow]

Hm. I use 1 or .5 depending on price I can get. I am always sure that the sediment isn't less than the carbon as that once caused me issues long ago.

One thing I have never done and am not sure what it means is "tune" the restrictor.

I get the restrictor rated for the membrane. The lever on it I keep at 90deg. Russ at buckeye says not to flush the membrane which is what opening that lever does. The only tuning would be slightly opening it. To what end though? That would reduce product water and I am getting 75gpd as rated. Doing this would rush water thru faster, presumably causing even faster decline.

I'd suspect any meter showing zero out of a membrane with incoming water out of any tap. No membrane has a 100% rejection rate.

[Vinny Kreyling]

You have to "tune" the water ratio for best membrane performance.
To do this you need to measure product "good" water against waste water for a specific time on both.
You should get a 4-1 ratio of waste to product. if you are not close you need to cut the flow restrictor to get there, or replace it if it's too short and start over.
I would go over this with Russ if you have any questions.

[Opus123]

Originally Posted by Vinny Kreyling

You have to "tune" the water ratio for best membrane performance.
To do this you need to measure product "good" water against waste water for a specific time on both.
You should get a 4-1 ratio of waste to product. if you are not close you need to cut the flow restrictor to get there, or replace it if it's too short and start over.
I would go over this with Russ if you have any questions.

Doesn't the ratio depend on the system? The spectrapure system runs at 3-1.

OP, maybe contact Spectrapure and see if they have any suggestions. You have a different kind of restrictor. On a lot of systems it is a piece that fits inside the waste line tubing and you can cut it down adjust the flow.

[ostrow]

Yeah, I have it at the end of my waste line. It's a valve. At 3o'clock it's closed, and you get product water. At 6 O'clock, it's open, and it flushes the membrane (which I am not instructed not to do any more).

I believe that's what they all are.
https://airwaterice.com/fast-flush-b...ictor-223.html