Would you change your RO filter and DI resin if....

Discussion in 'Water Chemistry' started by Todd_Sails, Feb 2, 2014.

to remove this notice and enjoy 3reef content with less ads. 3reef membership is free.

  1. Todd_Sails

    Todd_Sails Giant Squid

    Joined:
    Jul 3, 2011
    Messages:
    4,732
    Location:
    A Texan in S.E. Wisconsin
    Would you change your filters and resin, if
    noit only your RO/DI still read 0, but your RO tap on the sink also reads 0 tds?

    I was considering it, and already have the replacements, but 0 tds?
    I"m having NO water quality issues, none at all. And as I said, I"m still reading 0 tds after 2 years.
    My tap runs about 145 TDS fairly consistently. I have a $100, 5 stage system with the drinking water side also- got off Ebay.
    Water General Manufacturing Co.

    Also- my DI cannister was remounted to a vertical position, with the flow flowing from bottom to top- and the cannister is clear plastic, so as I can see the 'spent' part which is a browish, and the 'unspent' part whick is purpleish on the bottom. The resin in the clear cannister still has about 2/5'ths unspent.

    Now I have heard- 'oh, the bacteria will build up in the system after a year.'
    Why would it? Why a year- I think maybe that was a good interval to change things- but opps, I missed that.

    Also, I hear of people changing things when there DI reads 1 TDS.

    OK, so it's starting to get a little spent. BUT, lets say you started with the low # of 5 TDS.
    Are you aware that after you add the salt mix- it's over 1.000 TDS? I checked my DT- off the scale past 999tds.
    % wise speaking, how catastrophic would it be to use even as high as 5 TDS before you mix in the salt? Is the 5 TDS purely nitrate and Phos? I doubt it.

    I just feel some things are taken beyond the extreme in this hobby.
    I still love my DT and the hobby in general.

    [​IMG]
     
  2. Click Here!

  3. Mr. Bill

    Mr. Bill Native Floridian

    Joined:
    May 28, 2011
    Messages:
    4,874
    Location:
    USA
    FTR, nitrate and phosphate are not dissolved solids. Nitrate has neutral ions and are not read at all by a tds meter. Phosphate has weakly charged ions; given enough phosphate, you may get a low reading.

    That said, one would need to know what that 1 or 5 or whatever represents. With a private well, they're probably inert minerals. With some water systems however, it could be heavy metals which are not so harmless.

    I don't believe there is an actual timeline for changing your filters. Their longevity will depend on the quality of the water going in, and your tds meter will tell you when it's time to change. :)
     
    Last edited: Feb 2, 2014
  4. coylee_17

    coylee_17 Fire Goby

    Joined:
    Sep 7, 2008
    Messages:
    1,337
    Location:
    Peterborough, Ontario, Can
    Only sure fire way I know of to know when to replace filters is to monitor incoming and outgoing pressure. As the filters clog up, pressure drops. Poor filter maintenance can shorten the life of the membrane. If your water is only 145 TDS inbound then you can probably stretch your filters a little longer than most.

    So I guess to answer your question, yes you are still getting 0 TDS which is great, but we need to look at pressure to know if you are negatively affecting the membrane by prolonging changing the filters.
     
  5. Av8Bluewater

    Av8Bluewater Giant Squid

    Joined:
    Aug 27, 2008
    Messages:
    3,401
    Location:
    Dallas
    My BRS Chloramine plus is beeping at me to change stage 1. That's the sediment filter on my system. It is brown so I'll change it out soon. (set up in Oct. ) But FWIW my TDS reads zero. Pre Dual DI chambers read 7.
    If I did start getting TDS 1 I would go ahead and change it. I remember reading the literature on my old Typhoon system that said change it out in the 20-30 TDS range. So I don't think it's such a big deal to change it once it hits 1 it's just that I'm a little paranoid. My last tank I started losing some corals for unknown reasons so I just want to keep everything the best I can. If you haven't changed filters in two years I would be skeptical of a zero reading.
    Sediment filters are only $3-6 so not a big deal.
     
  6. AZDesertRat

    AZDesertRat Giant Squid

    Joined:
    Jul 30, 2009
    Messages:
    3,904
    Location:
    Phoenix AZ
    What are you testing with and what is your methodology?

    I find this very suspect.

    First off a RO membrane is a 90-98% efficient device so you will never have 0 TDS with RO only. Your meter may lack the low end accuracy needed to get a true reading or it may be out of calibration. If it is not temperature compensated it can be even further off.

    As someone already mentioned, phosphates and nitrates may not read well on a TDS meter as silicates do not either.
     
  7. Todd_Sails

    Todd_Sails Giant Squid

    Joined:
    Jul 3, 2011
    Messages:
    4,732
    Location:
    A Texan in S.E. Wisconsin
    Thanks AZD, I figured you would chime in, I was hoping anyways.

    You posts are the reason my DI is now vertically mounted, as we posted about over a year ago.
    I'm also still using the same ebay TDS handheld meter- probably not the best, but fairly accurate.

    NOt only is my DI resin cannister clear- to see the color change, but so is my sediment filter. Pretty sure it started white, it's now about 50% brownish/rust colored.

    My pressure is and has been about 52psi.

    I think I'll change things out soon, maybe within another 6 months, simply because of the age of them.
    But I have 0 water issues, my DT and coral growth has never been better.
     
  8. Click Here!

  9. AZDesertRat

    AZDesertRat Giant Squid

    Joined:
    Jul 30, 2009
    Messages:
    3,904
    Location:
    Phoenix AZ
    Try borrowing a good handheld TDS meter from a friend or fellow reef club member for a comparison. It is possible DI could last that long with your low TDS and an efficient RO membrane but what makes me suspect is the 0 TDS reading from the RO only. Even at 98% rejection rate which is very very good you should be seeing a reading of 1 or 2. My TDS is around 550 and at 99.4% rejection rate I am seeing between 2 and 3 using a COM-100 handheld which is capable of reading in tenths or decimals.


    The TDS or new saltwater is going to be somewhere over 32,000 TDS so I hope you have not attempted that with your TDS meter or if you did you immedediately triple rinsed it in RO/DI or distilled so it didn't permanently damage the meter.

    The reason your goal is 0 TDS is TDS measurement is not telling you anything specific so it could be silicates, phosphates, nitrates, copper, arsenic, iron, sodium......you have no idea what it is. Start out with pure water and use a trusted name brand salt mix and you can eliminate that nagging doubt, you know what you have and at what levels.
     
  10. Todd_Sails

    Todd_Sails Giant Squid

    Joined:
    Jul 3, 2011
    Messages:
    4,732
    Location:
    A Texan in S.E. Wisconsin
    Thanks again AZD- the RO/DI guru- I'm not worthy, I'm not worthy....

    I plan to use a fellow reefers TDS meter soon.
    When I used My handheld on my DT water- it blinked 999- as if it's off the scale of the meter. I did then re rinse it in my RO a few times, and it quickly read 0 again after 4 quick rinses.

    I'll probably change it sooner that later since I already have the replacement fiters and DI resin. I'll just change the color changed part of the resin actually. I really like that clear DI cannister for that reason.

    Thanks again AZD
     
  11. chris adams

    chris adams Purple Tang

    Joined:
    Oct 4, 2008
    Messages:
    1,828
    Location:
    Port Charlotte, FL
    how about some pics of your guys setups and list of models used.
     
  12. Todd_Sails

    Todd_Sails Giant Squid

    Joined:
    Jul 3, 2011
    Messages:
    4,732
    Location:
    A Texan in S.E. Wisconsin
    My RO/DI set up? It the Water General Manufacturing Co. RD106

    Welcome to Watergeneral Website the one stop shopping site for all your REPLACEMENT FILTERS / COMPONENTS FOR RO REVERSE OSMOSIS RO WATER SYSTEMS, whole house systems, water softners, uv systems, and shower filters.\

    http://www.watergeneral.com/product01.aspx

    AZD likes the Spectrapure- and for good objective reasons also.
    I'd go with Spectrapure- solely b/c he - a water science expert- says so

    Also, I had already ordered and installed this system I have- that I'm happy with before I read his posts on the subject.
     
    Last edited: Feb 3, 2014