RO Unit won't hold TDS and PH

[DiscusLoverJeff]

Hello friends,

I have a 5 stage RO unit (2 years old) and I just replaced the filters about 1 month ago. I replaced the membrane about 6 months ago (yes membrane is seated properly).

This is the brand I have currently

http://www.ebay.com/itm/Max-Water-5-stage-125GP-Reef-Aquarium-RO-DI-Reverse-Osmosis-Water-Filter-System-/200736461217?pt=LH_DefaultDomain_0&hash=item2ebcd351a1

My problem is, the TDS is 38 and PH is about 7.4 from the RO Unit. When new, the TDS was 2 and PH was 6.4. Now with all the new filters and membrane, what could be causing this spike? My tap water parameters have not changed as I monitor it monthly. Any ideas?

I was thinking of purchasing this brand as a secondary, anyone have any luck with it?

http://www.ebay.com/itm/150-GPD-6st-Reverse-Osmosis-RO-DI-Water-Filters-system?item=380326615149&cmd=ViewItem&_trksid=p5197.m1374&_trkparms=algo%3DPI.WATCH%26otn%3D8%26po%3DLCA%26p s%3D63%26clkid%3D7420884473972905754

Thanks,

Jeff

[DiscusOnly]

How/Where are you measuring the TDS?

[strungout]

Did something happen with your water source? When I measure tds its almost at 0.

[jimg]

I had a problem like that one time and found it was one of the black rubber gaskets was seated wrong on one of the filters and chlorine was ruining the membrane. also check flow restrictor and check valve

[DiscusLoverJeff]

What I did after the first week of installing the new filters and noticed the TDS were still high, I took everything apart and reinstalled them, same results. I made sure all filters and gaskets were installed properly. I changed them a year ago and had no issues.

Can't imagine a bad filter? I use 2 different TDS meters and both read the same TDS and PH. I might try replacing the membrane, but after only 6 months?

[TURQ64]

If you are moving water anywhere close to continuously, six months isn't unimaginable; I move a lot of water, and change membranes more frequently than that..those 'years' numbers are for water drinkers, not aquarists... what's wrong with the numbers??..My water's hard; zero never happens. Membranes have different ratings, if you will. If a filmtec membrane removes 95% of let's say '400+' tds, your output would read 38 easily..Also, many municipal water districts use multiple sources, causing fluctuation..

[Chicago Discus]

Jeff its time to change your membrane thats all thats wrong with it.... Gary we get our water from Lake Michigan same source it comes out of the tap at 180 TDS and 7.4 PH after twenty four Hours the PH will rise I think he needs to change his membrane.......Josie

[DiscusLoverJeff]

I have not found better reviews on a membrane other than Filmtec. Anyone have a better membrane? Most if not all membranes are rated for 2 years not 6 months. I am not sure that it should fail even at 75 to 100 gpd.

I will order one for sure, just not totally convinced it would last only 6 months.

[jimg]

I get about 2 yrs +- out of my membranes with 380 tds tap. and I use quite a bit of ro. it is possible that it sat on a shelf for some time.
imo filmtec are the best ge desal were next runners up. If you order another membrane get a check valve and new restrictor to.

[TURQ64]

Mine are all Filmtec..Just for YOUR info, I use around 14,000 gallons of RO product a month, so counting reject, well do the math ( about 40,000+g or so my bill says)..I'd love 2 years..just ordered six new membranes today...

edit..my bad math!

[texasdiscusman]

How often are you using your system?Dont think it does the membrane good just sitting there and no water Running thru it.If I remember RandalB would tell you to put system in a fridge if not running

[nc0gnet0]

I agree with Gary, 6 months of continual use is not out of the ordinary. Stop thinking about months of service and focus on gallons of service. Also, you need to change your pre-filters more often. If your AC block is shot, this will shorten your membrane life considerably. How often do you flush your membranes? Membrane life is a product of many factors such as water pressure, source water contaminates, temperature etc.

[DiscusLoverJeff]

Ordered new membrane, flush kit and inline TDS meter to keep better track of whats going on.

Using my RO daily (about 75 gallons avg per day, weekend I max it out at 150 per day) my system does not sit idol. I have found that my water pressure is steady and tap water quality is steady.

I contacted my village and asked them when they schedule their hydrate flushing and they do it 3 times per year with one coming up next week. I am not sure in anyone elses area if they do this but after they do it in my area, I have to run the water for 30 minutes out of each faucet, bathrooms, sinks etc. to clear the brown water. Once that is done I retest the quality.

Thanks for the advice.

Jeff

[DiscusLoverJeff]

Just an update on my TDS and PH. After changing everything from filters to membrane, the TDS is still at 30. I know I mentioned that my membrane was not that old (although I did not mind changing it), I felt that it was not the issue. So somewhere I have a problem.

A TDS of 30 is not bad for what we all use RO water for, it's just the principle that after gutting my system and startiing over, I should of expected better results. I even went as far as installing a flush valve and inline TDS meter. My tap water after 2 years has not changed and is holding steady at 230/235.

Other than buying a new system, the only thing left that I could replace would be the hoses.

Thanks for all the advice.

[jimg]

check valve or flow restrictor are still my thoughts

[tommyhlx]

Hi guys. I have the same problem too. My RO system was working fine for several month then it stop producing or lowering my ph. It seems like there's water coming from the waste outline but not the good water outline of the reverese housing. I even order new replacement filters as well as a filmtec ro membrane but same issue. Please help.........................

tommy

[jimg]

Hi guys. I have the same problem too. My RO system was working fine for several month then it stop producing or lowering my ph. It seems like there's water coming from the waste outline but not the good water outline of the reverese housing. I even order new replacement filters as well as a filmtec ro membrane but same issue. Please help.........................

tommycould be too low pressure, check valve,fouled carbon filters letting chlorine into membrane

[Buckeye Field Supply]

Hello friends,

I have a 5 stage RO unit (2 years old) and I just replaced the filters about 1 month ago. I replaced the membrane about 6 months ago (yes membrane is seated properly).

This is the brand I have currently

http://www.ebay.com/itm/Max-Water-5-stage-125GP-Reef-Aquarium-RO-DI-Reverse-Osmosis-Water-Filter-System-/200736461217?pt=LH_DefaultDomain_0&hash=item2ebcd351a1

My problem is, the TDS is 38 and PH is about 7.4 from the RO Unit. When new, the TDS was 2 and PH was 6.4. Now with all the new filters and membrane, what could be causing this spike? My tap water parameters have not changed as I monitor it monthly. Any ideas?

I was thinking of purchasing this brand as a secondary, anyone have any luck with it?

http://www.ebay.com/itm/150-GPD-6st-Reverse-Osmosis-RO-DI-Water-Filters-system?item=380326615149&cmd=ViewItem&_trksid=p5197.m1374&_trkparms=algo%3DPI.WATCH%26otn%3D8%26po%3DLCA%26p s%3D63%26clkid%3D7420884473972905754

Thanks,

Jeff

If your RO water is 38 ppm, and your tap water is 230 ppm, then you can calculate your membrane rejection rate like this:

(230-32) / 230 =
0.86 or 86%.

That's pretty bad. Depending upon which membrane you have, it should be at least 90%.

Do you know what brand of membrane they use?

Russ

[Buckeye Field Supply]

First, check the water pressure at the membrane. Looks like that cut-rate system you bought didn't come with a pressure gauge, but an add-on p-gauge kit is not expensive and it is easy to add. What difference does the pressure make? The membrane's rejection rate is reduced significantly at lower pressures. Here's some data for a membrane with a 98% rejection rate:

http://i224.photobucket.com/albums/dd293/BuckeyeFS/Pressurevsrejection-2.jpg

[Buckeye Field Supply]

BTW - are you still using a GAC prefilter? If so, I'd get rid of it. GAC prefilters are ok for drinking water RO's doing only a few gpd - but they have no place in systems for this hobby. If you see a system with a GAC prefilter and a high capacity membrane (e.g., 75 gpd) you might want to consider a different vendor.

[Buckeye Field Supply]

Hi guys. I have the same problem too. My RO system was working fine for several month then it stop producing or lowering my ph. It seems like there's water coming from the waste outline but not the good water outline of the reverese housing. I even order new replacement filters as well as a filmtec ro membrane but same issue. Please help.........................


We can help you troubleshoot your system. If you'd like, give us a call when you are in front of the system. Have recent TDS readings for your tap water and RO water available before you call.

Russ
513-312-2343

[DiscusLoverJeff]

Hi Russ,

Thanks for all the advice. Well after 4 days with the new membrane, the TDS finally came down to 18. But now, the flow is less than I had with my previous membrane even though they are both 150 gpd.

So everything is new in this system, membrane, filters, flow restrictor (a 1200, rated for 150 gpd), inline TDS meter and flush valve. Unfortunetly now though, I am getting less per gallon and a lot more waste water. As a matter of fact, the watse water runs almost as fast as the faucet water, lol.

Not sure now what I am going to do abouth this.

[Ioan C.]

Hi Jeff,
Not sure now what I am going to do abouth this.I can tell you what is for sure: your hobby will be more expensive. Why was the RO water bad before? Why do you need a lower hardness than the one from the old membrane?

[Buckeye Field Supply]

Hi Russ,

Thanks for all the advice. Well after 4 days with the new membrane, the TDS finally came down to 18. But now, the flow is less than I had with my previous membrane even though they are both 150 gpd.

So everything is new in this system, membrane, filters, flow restrictor (a 1200, rated for 150 gpd), inline TDS meter and flush valve. Unfortunetly now though, I am getting less per gallon and a lot more waste water. As a matter of fact, the watse water runs almost as fast as the faucet water, lol.

Not sure now what I am going to do abouth this.

Troubleshooting is pretty tedious to do via email or bulletin board posts - please give us a call when you're in front of the system - we're happy to help. We have some ideas for you re: water pressure, flush valve, waste to permeate ratio, water temperature, feedwater TDS, your prefilters, etc, etc...

Russ
513-312-2343

[DiscusLoverJeff]

Hi Jeff,I can tell you what is for sure: your hobby will be more expensive. Why was the RO water bad before? Why do you need a lower hardness than the one from the old membrane?

Well others noted that 6 months on my old membrane was long enough and that was a possible reason for the climb in TDS and PH.

I was sceptical about changing it, but did it anyway.

I might just order another brand membrane, but I will call Russ when I get home from work and get in front of the RO unit and wait for his advice.

[nc0gnet0]

It is possible that is the best your brand of membrane can do. Or, have you considered your TDS meter is out of calibration? 150 gallon a day membranes do tend to allow more to get through IME.

[DiscusLoverJeff]

I have 3 TDS meters and all read the same.

[Buckeye Field Supply]

Here's some info on the membranes we work with most often. All are Filmtec except to 150 gpd:

http://i224.photobucket.com/albums/dd293/BuckeyeFS/ROMembraneFactorySpecs-1.jpg

Russ

[Flosty]

I know this is a oldish thread but when I had a problem with my R/O it was the 4 way valve that controlled tank filling and drain water that had the fault.
My tds was high and my tank was filling way to quickly,though I use a pump so it was easy to tell that it was filling to quick.
Just a thought for those that may be reading the thread and have a similar problem.