RO Smell

So I bought a RO/DI unit

https://www.maxwaterflow.com/6-stag...o-di-hm-inline-tds-meter-50180-gpd_p_887.html

and I let it sit for about 4 months. There was a huge problem at work and I did not even have time to think =/

I set it up and was running water threw the RO part and skipping the DI part just to watch the TDS. Well my tap TDS is 165,

and the unit has been running now for about 45min. I am getting a sulfer smell in the grey, and the good water line, but the

TDS is down to 7... what could be causing this smell? I can only think of something with bacteria since I am not even using the DI part??

Any thoughts?

 

If you hooked up the waste water line to the drain then you could be smelling the stuff that has been disturbed in the old drain pipe. Put some product water in a glass and try to smell it in another room.

 

Crud will grow in a RO system even when its running. In one that's been left to sit, I can only imagine what might get started in the various lines, tanks, and the filter beds.

Usually, the water goes through a carbon filter fairly soon in the process. After that, there's no disinfectant in the water. That's great, and is a lot easier on the RO membrane. But it also means algae, bacteria, fingi, etc., can grow in the lines, filters, and containers in the system.

In the labs where I worked, the RODI water was very low conductivity. Ultrapure grade. Yet it always smelled like a day at the lake, with a dead carp washed up next to you! This was probably from algae growing in the lines. Algae is reponsible for many taste and odor complaints. I certainly would never dream of drinking the lab RODI water!

Confirming this, the chief microbiologist at the main lab said she'd noticed the same thing at all of the labs, and she tested the water from the system at her lab, and said the bacteria counts from it were sky high. She used a different system and a very fine filter (as did the micro labs at the other labs) to assure they had sterile water for their work. For most other lab analysis, this is of no concern. But it just seemed kind of surprising to me. After all, what does the bacteria and algae eat in a system like that?

Further, doing contract work at a local regional hospital, I was working with their people, testing the conductivity at various taps in their RODI system, and they said they'd switched all of the piping and tubing to totally opaque material to try to keep light out of their system to help suppress algae growth, and, they flushed the entire system once per month with hydrogen peroxide to further suppress algae and bacterial growth in the system.

It would not surprise me in the least to find all manner of growth in a stagnant RO system.

I guess the question is: What should be done to clean it out and get it ready to run again?

 

Hi,
I haven't experienced any problems with my RODI unit, so the following is just a best guess.

Disassemble the RO unit, take out all the filters, the membrane etc and replace the replaceables (pre filter/sediment, carbon filter, DI resin), replace the membrane if you think it's necessary.

Rinse/wash all the containers, tubes etc with a warm bleach solution.

Rinse again with fresh water.

Reassemble everything, let it run and see if it gets better.

Again, I have no experience, but I guess it could work.

 

Alright, the smell was in the product water after I took to a different room. So I started dissembling the unit and came across

the issue. One of the carbon filters had a plastic piece on the top and there was a small piece missing from it, so it was

leaking carbon into the 3rd chamber. I am going to replace all the filters except for the sediment filter since the problem was

after that. I decided to go with a different membrane, so I ordered this one along with a new 550ml pressure regulator.




Now I have a question about the sediment filter. 5 micron, 1 micron, or best of both worlds and buy a extra canister and start

with a 5micron, then go to 1micron? Not sure if it would be worth the extra $20 for a extra sediment filter...

 

I can't answer the proper pore size question, but I'd recommend also using some hydrogen peroxide to wash, rinse, soak all of the lines and filter containers. Hydrogen peroxide is easy on plastics, but murder on fungus and algae, and fairly effective on bacteria and viruses, too. You can get a quart of 3% H2O2 at Wal Mart for 88 cents. So you can get a lot for pretty cheap. It's good cheap insurance. It rinses clean from plastics very easily, too, and a bit of it in a fish tank would likely not cause any problems anyhow. Great stuff, IMO.

The carbon getting into where it didn't belong was likely not the cause of the smell, but it's good to get that fixed, anyhow. The sulfur smell was likely H2S from anaerobic bacteria growing in the system reducing sulfur compounds into H2S while it all sat dormant.

Some systems place a carbon filter at the end of the filter chain to help with taste and odor. Activated carbon is very good for removing taste and odor. The activated carbon on the "front end" is to remove chlorine, which can damage your RO membrane. But once you remove the disinfectant in a water system, the opportunity for microbial growth is increased, so you need to be diligent and vigilant if it's important to avoid growth in the system beyond that point.

In the labs, people did not drink the RODI. It was just for analytical use. So other than the microbiology labs, most departments did not worry about the microbiological safety of the RODI water.

In the hospital and microbiology departments, on the other hand, they did take steps to avoid growth of microbes in their RODI systems.

If I was using an RO system for drinking water, I'd be fairly careful to keep things clean in the system, especially past the first activated carbon filter. Even when using only an activated carbon filter for drinking water, its wise to clean and disinfect the system beyond the carbon filter periodically, because you have no disinfectant in the system beyond the AC.

For fish-only use, I'm not sure how much hazard this all presents to the fish. An aquarium has algae and bacteria galore anyhow. You wouldn't drink aquarium water, and getting some splashed in your eye or even into an open cut can theoretically expose you to problems such as "fish tuberculosis".

 

Good job upgrading the membrane along with the correct flow restrictor for 75GPD membranes. Did you get the flush valve style flow restrictor combo? Don't forget to remove your old flow restrictor. As for the pore size it's wise to go from larger to smaller. It's pointless to go the opposite. I recommend going from a 5 Micron Premium ROsave.Z sediment filter so it would not clog soon. For the first carbon block you can get 1 micron BRS Universal and 0.6 micron Matrikx CTO Plus for the second.

https://www.bulkreefsupply.com/membrane-flush-valve.html

https://www.bulkreefsupply.com/ge-rosave-z-depth-sediment-filter.html

https://www.bulkreefsupply.com/brs-universal-carbon-block-filter-1-micron.html

https://www.bulkreefsupply.com/10-matrikx-carbon-block.html

FYI, my system never goes stagnant since it has a pressure tank and hooked up to the fridge and RO faucet (tapped on a tee before DI). If you want to get a drinking water kit it should come with a check valve so that the membrane and DI resin does not see back pressure from the pressurized tank.

 

For the sediment filter, the bigger the sediment filter, the bigger the particles getting to the RO membrane that it has to reject. This can decrease the life of the membrane.

For that reason, I only use 1 micron sediment filters, they're much cheaper than RO membranes

 

I guess my reasoning for the decreasing pore size is to time the replacement of the sediment and carbon filters. This is so you can replace them all at once and not have to replace the sediment filter more often than the carbon blocks. Remember the third carbon block is 0.6 microns so only half a micron particles get to the membrane/s.

 

I really liked the idea going from a 5 micron, 1, and then a .6 micron filter. So I purchased them all online and have my unit running. I rinsed everything out and let the unit run for awhile to make sure everything was good and TDS went down.

I put a T after the membrane so that way I can get some RO water for drinking. Everything I thought was running great, I had 2PPM TDS off of the membrane, and 0 out of the DI. Then I made 40 gallons of RODI water for my tank. Well I made some RO water and put it in a pitcher in my fidge. Once it was cold I drank a couple glasses. That was some delicious tasting water!!

Well I noticed I had really bad heartburn later and the water was the only thing I had for a long time... So I did a PH test on the RO water. Well its 6 or below... So I believe that is why I had heartburn. Well I did not want to be drinking that acidic of water so I moved my T fitting before the membrane. First thing I did was check the TDS. My tap is around 165, but when I checked the water it was at 205!!

I thought maybe it was cause the water pressure was much greater and caused the spike. So I put a valve on it and turned it so it was coming out as slow as the membrane. I let it run for 2 min just to hopefully get a better reading, and the lowest it got was 184. Why is it higher after a 3 stage filter? Am I getting a false reading somehow after the 3rd filter?

I just want to be able to use it for drinking and the tanks...

 

I really liked the idea going from a 5 micron, 1, and then a .6 micron filter. So I purchased them all online and have my unit running. I rinsed everything out and let the unit run for awhile to make sure everything was good and TDS went down.

I put a T after the membrane so that way I can get some RO water for drinking. Everything I thought was running great, I had 2PPM TDS off of the membrane, and 0 out of the DI. Then I made 40 gallons of RODI water for my tank. Well I made some RO water and put it in a pitcher in my fidge. Once it was cold I drank a couple glasses. That was some delicious tasting water!!

Well I noticed I had really bad heartburn later and the water was the only thing I had for a long time... So I did a PH test on the RO water. Well its 6 or below... So I believe that is why I had heartburn. Well I did not want to be drinking that acidic of water so I moved my T fitting before the membrane. First thing I did was check the TDS. My tap is around 165, but when I checked the water it was at 205!!

I thought maybe it was cause the water pressure was much greater and caused the spike. So I put a valve on it and turned it so it was coming out as slow as the membrane. I let it run for 2 min just to hopefully get a better reading, and the lowest it got was 184. Why is it higher after a 3 stage filter? Am I getting a false reading somehow after the 3rd filter?

I just want to be able to use it for drinking and the tanks...

There may be some residual pressure at the membrane and DI canister. If you tapped a T line after the carbon and before the membrane you may be pulling some water from the membrane. This water will include product and waste water hence the high TDS. This can also wear down your membrane prematurely. Install a check valve before the membrane to prevent backward flow.

EDIT: I forgot there is an elbow check valve on the membrane housing at the product water side so the added TDS you saw was probably only coming from waste water. So install that additional check valve so water will not flow backwards from the membrane.

You can also buy an alkaline cartridge for drinking water. But do not install this before the DI resin. The added TDS will deplete DI prematurely.

 

I really liked the idea going from a 5 micron, 1, and then a .6 micron filter. So I purchased them all online and have my unit running. I rinsed everything out and let the unit run for awhile to make sure everything was good and TDS went down.

I put a T after the membrane so that way I can get some RO water for drinking. Everything I thought was running great, I had 2PPM TDS off of the membrane, and 0 out of the DI. Then I made 40 gallons of RODI water for my tank. Well I made some RO water and put it in a pitcher in my fidge. Once it was cold I drank a couple glasses. That was some delicious tasting water!!

Well I noticed I had really bad heartburn later and the water was the only thing I had for a long time... So I did a PH test on the RO water. Well its 6 or below... So I believe that is why I had heartburn. Well I did not want to be drinking that acidic of water so I moved my T fitting before the membrane. First thing I did was check the TDS. My tap is around 165, but when I checked the water it was at 205!!

I thought maybe it was cause the water pressure was much greater and caused the spike. So I put a valve on it and turned it so it was coming out as slow as the membrane. I let it run for 2 min just to hopefully get a better reading, and the lowest it got was 184. Why is it higher after a 3 stage filter? Am I getting a false reading somehow after the 3rd filter?

I just want to be able to use it for drinking and the tanks...

As long as the RO water is microbiologically safe (no pathogens growing in the system and the water), it should be just fine to drink.

The pH of ultrapure water will often read as being a bit acidic. But the thing to realize is that because this water has almost no ions in it (as measured with your conductivity probe), it's "ionic strength" is extremely low. pH readings made on very pure water are often misleading or inaccurate.



So while the pH may measure somewhat low, ultrapure water cannot have much if any titratable acidity or titratable alkalinity. If you did a titration to measure the acidity of your RO water, it would probably come up nearly zero!

Also, remember that your stomach is loaded with rather strong hydrochloric acid. If you were to measure the pH in your stomach, it'd probably be below 3.5 (often well below that). And the fluid in your stomach will have a rather high titratable acidity, and very high conductivity. In short, the wimpy RO water will be no match at all for the very high ionic strength acid that's already in your stomach.



So I don't think the pH of the RO water would have any effect whatsoever on the pH of your stomach except to dilute it all down. On the other hand, your starting tap water may behave as something of an antacid! It's likely got some carbonate hardness to it which would help neutralize stomach acid. Again, though, it would probably not be enough to really do you much good, but I just thought I'd toss that out there.

Heartburn is really a matter of the stomach acid getting to where it doesn't belong - getting to places that are not properly protected against it. In the stomach, it's fine. In your esophagus or throat, though, it burns!

Different things can cause Gastroesophageal Reflux (stomach acid escaping your stomach and getting up into your esophagus). It might have been the RO water, but that seems highly unlikely.

I'd reconnect your drinking water tap where you had it. You might still want another activated carbon filter after that tap, but before your drinking/ice-cube water connections. That ought to be some excellent tasting water!

Some people believe that you shouldn't drink RO water because it will strip the minerals out of your body. I'd say that if you eat a balanced diet, that can't be much of an issue. But there's no denying that we might get some of our minerals out of the "hard" water we drink.

I know people who have nasty well water. They use a water softener to remove most of the hardness. Then they use an RO system after that to get their drinking water so that they get rid of the sodium that the softener adds. It's some of the most excellent tasting ice and water I've ever had. And they've been drinking it for many years.

I can't say if drinking RO water is undesirable or not, really. But I don't think the pH of your RO water was the cause of your heartburn. I think it was likely coincidental and caused by something else. But maybe there's something else about your RO water that gave you heartburn.

If it was me, I'd reconnect it the way you had it and give it another try. I know that using RO water for your icemaker keeps the cubes from having the chunks of scale in/on them that you get when using regular water around these parts.

Then again, that very scale is somewhat like what's in Tums or Rolaids. So NOT having that in your water will be a very very slight change, I guess. But I still don't think it would be significant.