Help TDS through the roof and so is my DI resin budget!

Discussion in 'General Equipment, Hardware, Filtration' started by Bradley Keck, Sep 5, 2018.

  1. Bradley Keck

    Bradley Keck Active Member R2R Supporter

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    Hello everyone!

    I'm in the process of setting up my first saltwater aquarium, a 150g 60x24x24. I have a BRS 6 stage RODI 75gpd unit. I finished my salt mixing station back in June and decided to go ahead and try it out although I was not ready to fill the tank. I made 100g of RODI and my TDS after the membrane read about 20-40 typically. After a total of about 150g of RODI, I had depleted almost one cartridge of DI resin. I stored the RODI until the beginning of August when the tank was ready to be leak tested and filled. Once I got the tank filled, I started to make more RODI. The TDS after the membrane all of sudden started reading as high as the 180's! I went through a whole cartridge of DI resin after only 20-30g, and it seemed to take much longer to make RODI water. I live in Indianapolis. The average TDS straight from the tap is around 400TDS with some areas a slow as 200 and some as high as 600. My pressure has consistently been at 50PSI both when it was working right and now. I contacted BRS and they suggested maybe a faulty membrane, so I bought another. Made no difference. I have run another 40g through the new membrane and am still getting readings in the 160-190 range after the membrane. The TDS after the first and 2nd di cartridge does read 0, but like I said, I am going through DI resin like crazy.. I contacted a LFS that uses city water, and they have not experienced any problems that they are aware of. Any ideas what the heck is going on? For good measure, even though I detect no ammonia in the RODI water and my pressure has not dropped, I replaced both carbon blocks and sediment filter. It made no difference. :rolleyes:
     
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  2. Bradley Keck

    Bradley Keck Active Member R2R Supporter

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    Oh, and yes I have from day one flushed the membrane for 5-10 minutes before and after use. Could it be that water is getting past the membrane somehow?
     
  3. KStatefan

    KStatefan Active Member

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    Something is not right. You should be getting at least 95% rejection.

    Is the membrane seated all the way?

    What is the ratio of waste water to good water?

    I would not run any more thru the DI until you get this figured out
     
    Last edited: Sep 5, 2018
  4. chipmunkofdoom2

    chipmunkofdoom2 Always Making Something R2R Supporter Reef Squad R2R Excellence Award Article Contributor

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    @KStatefan is right. Unless your tap water has between 400 and 800 ppm TDS, something is not right. What is your tap water measuring in TDS?

    EDIT: Re-read your post, saw 160 - 180 ppm TDS after membrane. This is not right unless your tap water has 3,200 ppm TDS or higher.
     
    Last edited: Sep 5, 2018
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  5. chipmunkofdoom2

    chipmunkofdoom2 Always Making Something R2R Supporter Reef Squad R2R Excellence Award Article Contributor

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    Carbon blocks and sediment filters have almost no effect on final water quality whatsoever. Carbon blocks and sediment filters are used in RO systems primarily to protect the RO membrane from chlorine/chloramines and large particles.

    Focus on your RO membrane. Something isn't right here, unless as stated above, you have really high tap TDS. Even then, you can still probably improve the rejection rate.
     
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  6. Bradley Keck

    Bradley Keck Active Member R2R Supporter

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    Thank You for the responses! I know this cannot be right. It is indeed 160-180 and I do realize that would mean a TDS of 1600 to 1800 which is crazy. I had to do a double take when I first read it. I know the sediment filter and carbon blocks have nothing to do with the TDS, but I was desperate to try and figure out something. As far as what my TDS are straight from the tap, I have not directly measured, but I know per yearly city water reports it runs b/t 200-600 tds. What really has me puzzled is it worked perfectly fine for the first 180g or so. I did not change a thing. It did sit for about 4 weeks before I started making water again, but that was it. I had not changed a thing. Then, despite knowing that there is no way the membrane should need replaced, I replaced it and it did not change a thing. This is probably pretty normal, but I have noticed when I first turn it on, it will read around 40-60tds and then it climbs for the first hour a or so until hits around 160-180( that part NOT normal;). I am wondering since two different membranes have given the same result, if it does not seat properly now. Could something having been screwed up while it sat for month? I agree with you guys though that this has to be something with water getting past the membrane somehow and it would have to be a problem that would not be fixed by replacing the membrane and reseating it. Frustrating, because I have been waiting two years to get my tank actually stocked with something alive. I have had 88# of cured pukani in the tank for 4 weeks and some 30# of imported live rock for 3 week. I am ready for my CUC, but am not going to do it when I cannot get water made. I feel like this whole thing with it producing water much more slowly has something to do with it as well. I have not measured my ratio of waste to RODI, but production is about half what it was. I was getting about 30g in 10-14 hours, and now about 15 in that time period.
     
  7. Geebs19

    Geebs19 Give me all the Euphyllia R2R Supporter Build Thread Contributor

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    I would try and replumb everything so that you can ensure that lines are going into the correct areas. Sounds like water is bypassing or just shooting straight through one of the canisters. I know this isnt the issue but I would see if you could increase that pressure, 50 is the lowest you want and still isnt that great. Just really odd that it would work for the first 180 gallons and then just die off.
     
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  8. chipmunkofdoom2

    chipmunkofdoom2 Always Making Something R2R Supporter Reef Squad R2R Excellence Award Article Contributor

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    Nothing will go wrong with an RO/DI system left sitting, except that the membrane should not be allowed to dry out (although you mentioned you replaced it, so you should be fine there). Another thing worth mentioning is that when you install new carbon blocks, fines and dust can clog the membrane if you don't bypass the membrane at first and flush those down the drain.

    If you're getting 15 gallons of product water in 10 hours, something is wrong. Please post some pictures of your unit. It's possible you didn't hook up the flow restrictor properly, or maybe the bypass valve was left open. It's also possible that something is still getting by the membrane, which could explain the high TDS as well as low production. 30 gallons in 10 - 12 hours is about normal, as that would be about 60 - 70 GPD. 15 gallons in 10 - 12 hours is not normal at all.

    You really should have a handheld meter and know your tap water TDS. It sounds like something is wrong with the membrane here, but it's possible that your TDS is actually closer to 1,000 ppm, in which case, you're probably not going to get a whole lot better than 20 - 40 ppm TDS post membrane. We can't know that for sure though because we don't know the tap TDS. This will also help you decide if a booster pump would be a worthwhile purchase after we get the issues sorted out. Right now we can't make that call because we just don't know.
     
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  9. Bradley Keck

    Bradley Keck Active Member R2R Supporter

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    Exactly!! makes no sense! I know that 50psi is the minimum, but as I understand it, pressure would effect the rate and waste to RODI ratio, but should not affect TDS? I had already thought about getting a booster pump maybe at Christmas or something, but not until I get this figured out.
     
  10. Geebs19

    Geebs19 Give me all the Euphyllia R2R Supporter Build Thread Contributor

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    Ya, like I said above I know thats not the issue. Just figured I would mention it. A boost in PSI will help conserve DI later on once you get this issue figured out.
     
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  11. chipmunkofdoom2

    chipmunkofdoom2 Always Making Something R2R Supporter Reef Squad R2R Excellence Award Article Contributor

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    This is not true. If you don't change your flow restrictor, then yes, changing pressure will affect your waste to product ratio. But, whenever you change your pressure, you should always check your waste to product ratio and get a new restrictor if necessary. If you add pressure to a system and don't allow more water to go down the drain as waste, you're forcing more water through the membrane, which will lead to mineral accumulation on the membrane's film and ruin it prematurely.

    Adding pressure and using an appropriate flow restrictor, however, will generally give you higher rejection rates. This means purer water out of the membrane, which means less of a strain on your DI resin.
     
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  12. Derek Clifford

    Derek Clifford Member

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    Put up some photos of your setup. Especially of the RO section of the unit and its tubing.
     
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  13. Bradley Keck

    Bradley Keck Active Member R2R Supporter

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    Well, tally another rookie mistake. I did not bypass the membrane when I installed the new carbon blocks. I did make sure to ditch the first hours worth of RODI - about an inch of water in a 5g bucket, but I did not bypass the membrane. When the membrane has been flushed for about 5-10 minutes after making water, I turn off the source water and the wait for the pressure to drop to zero. I do not close the flush valve at this point because the first thing I will do before making more water is flush it for another 5 minutes or so. Should I not leave the flush valve open when not in use? I see what your saying regarding my source water TDS. I have referenced it through yearly tests and samples taken here in indy every year, but I guess you never really know for sure unless you test it. I will look into a hand held meter. I just hate to buy something I may only use once. Never felt the need for one until now. Thank You for your help, its reassuring to know there is a community of people ready to help in this hobby. Lord knows I need it!
     
  14. Bradley Keck

    Bradley Keck Active Member R2R Supporter

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    Thank You! So, when I get a booster pump, I will need to get a new restrictor or at least check my waste/to product water ratio to make sure things are good with the new pressure rate.
     
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  15. Bradley Keck

    Bradley Keck Active Member R2R Supporter

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    BRS supplies this thing with everything already installed. Literally all I did was hook up the source water and installed the float valve on my container, but I wondered if gremlins were at play here so to speak. maybe someone accidently knocked something off, who knows, but I was thinking the same thing. I need to take this thing down and go through each part of it.
     
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  16. Bradley Keck

    Bradley Keck Active Member R2R Supporter

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    I will do that pronto. I have been putting off being able to post-pics - I have not even started my build thread and I want to sooo bad. I have been wanting to show my salt mix station anyways. Nothing fancy, but I am proud of it! I'm not a DIY kind of guy usually ;)
     
  17. chipmunkofdoom2

    chipmunkofdoom2 Always Making Something R2R Supporter Reef Squad R2R Excellence Award Article Contributor

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    This might be part of the problem. RO membranes should not be allowed to dry out. When you leave the valves open with the system off, you're allowing water to drain out of the unit. It's possible the membrane is drying out, which will ruin it. You should close a valve on the output line when you're done making water and allow the system to pressurize until the auto-shutoff turns off the flow. Better yet, install a float valve on your freshwater reservoir so that the unit shuts itself off when you have enough water. This could explain why the unit works fine for the first 180 gallons or so, then the TDS skyrockets. After the membrane has a few cycles of drying out, it's possible it's too damaged to function properly.

    It's also debatable if flushing your membrane is actually doing anything. Some say yes, some (who actually work in waste water treatment) say no. But at the very least, you should not allow your unit to drain between uses.
     
  18. MnFish1

    MnFish1 Valuable Member R2R Supporter Partner Member 2019 Build Thread Contributor

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    Maybe try a new tds meter first.
     
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  19. Simplicity Aquatics

    Simplicity Aquatics Simple, Effective, Affordable R2R Supporter Gold Sponsor

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    What kind of flow restrictor does it have? Is it one of the capillary versions and are you sure it is installed in the right place and trimmed to length?
     
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  20. Bradley Keck

    Bradley Keck Active Member R2R Supporter

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    Good to know! Yet another rookie mistake! Like you said that maybe part of the problem, but cannot be all of it as the new membrane showed the exact same readings from day one. I have a float valve on my freshwater storage tank, but it is at the top and I would have to make 50gallons for it shut off on its own. What I will do from now on is flush for 5 minutes before shutting off the source water and then close the flush valve before shutting off the source water. Thank you!!
     
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