How to Select an RODI Unit w/tips for those of you who already own one)

Using only 0 TDS RODI water is a foundational element of keeping a saltwater aquarium.

With all the choices on the market though, how would you decide which RODI unit to buy? And wouldn’t the unit you can buy at Home Depot or Lowe’s work just as well? Once you have an RODI unit, you’re set right?

This episode of Mr. Saltwater Tank TV answers these questions, gets up close and personal with RODI units, and includes tips for those of you who already own an RODI unit.

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Comments for this article (28)

  • Brad Mugleston says:

    PSI – ours is over 50 – how high is OK?

  • is that the psi before the sediment filter or right before the RO membrane?

  • Kam says:

    wait a can drink the RODI waste water? My in TDS water is like 139 and waste water TDS is 170…can you really drink them?

  • Kam…I don’t drink the waste water. I drink the good RODI water.

  • Kam says:

    why would you drink the rodi water? It’s stripped to bare water without the useful minerals that humans used…

  • jeff says:

    hey mark are they easy to install, is the laundry the most popular place to install them, thanks for another great video

  • Jeff…happy new year to you as well.

    The laundry room is popular b/c it is easy to tap into the cold water outlet for your washer. The hardest part for me was finding the studs in the wall to make sure the unit was securely in place.

  • Kam, I use the RODI water to make things such as tea. The tea puts the minerals back into the water. But with the nasty chlorine/chloramine/etc out, the tea, etc tastes better

  • BBMarlin says:

    Great video Mark! I thought I would mention a little something for those that do not have the space or time to install one of these units inside their home. I installed mine on my garage wall and use a sprinkler timer so I can manage the amount of water that I am creating. I drag my water hose into my garage, set my timer for 2 hours and net 5 gallons of RO/DI water from my 75G / day unit. Simple set it and forget it way of creating RO/DI water! Timers are cheap and can be found at Home Depot or Lowes.

  • Dan says:

    Another fantastically helpful video, Mark. I’m expecting my RO/DI unit tomorrow. Think I’ll fix up a nice, tall glass of iced tea!

    BBMarlin, nice tip about the timer. I’m facing the same situation. I will have to install my unit in the garage as well and I was trying to come up with a good way to meter the water production. Thanks for a great idea!

  • Elizabeth says:

    Awesome video, got my Buckeye unit up and running…can you linky the specific TDS measurer you are using? Much thanks!!

  • E…The way Buckeye’s site is setup, I can’t link to it directly, but it is model BFS-75 meter for $22.20 on this page:

  • Alicia says:

    I am trying to purchase one of these, and have been shopping around for some time now. My question is that when I do get one (I think I’m ready to make my purchase), is there any need to add in trace minerals and what not? I have been told by my lfs (unreliable in the SW fish knowledge) that if I use RO/DI water I will need to replace some things that get taken out. I’m I again being fed a line of bull$#@! or are there trace minerals that I need to get along with the RO?DI system? Personally, I thought that the salt mixture I am using had those in it, so I guess my question comes down to whether or not my lfs is trying to sell me crap that I really don’t need (…. again).

    Your videos and help are appreciated!

  • Alicia…yes RO/DI units strip the water of pretty much anything in it.

    However, your salt mix will put the minerals back in that your tank needs. You don’t need to supplement it with other trace minerals though.

  • Dan says:


    Don’t worry about adding trace minerals to your RO/DI water for topping off your tank. Remember, when water evaporates, all that leaves your tank is pure, fresh water. All of the other “stuff” stays behind, including trace minerals and salt. Your salt mix will take care of the rest when you do your weekly 5% water changes, like Mark said.

  • Paco B. says:

    Is there a setup guide on how to install the unit ?

  • Paco…Buckeye Field Supply provides you with instructions on how to install the unit. They are very easy to follow.

  • Paco B. says:

    Thanks Mark for answering all the questions we ask, so LED lighting good or not im looking on making this energy efficient also whats a good size sump and where can i get one not so expensive for my 60 gallon tank … thanks Mark …

  • Mark F says:

    Markie Mark,
    How do you know which filters to change???
    Thanks for all the great info!

  • Mark…I pull my filters every 6 months (that’s about how often my DI bed goes bad). The DI bed when it goes bad, and the RO membrane every 12-18 months.

  • Brian Davis says:

    Hehe, I like using my RODI water in my NasaFlo Neti Pot (;

    Appreciate the information Mark, fantastic what you’re doing. I need to order some stuff when you have time (:

    Thanks n

  • What the heck is a NasaFlo Neti Pot Brian?

  • Bedlamer says:

    I had no idea on what a NasaFlo Neti Pot was either. Apparently its a teapot shaped thing for essentially giving yourself a nasal enema used by some yoga practicioners. Not my cup of tea though.

  • Bedlamer…we that clears that up! Anyone want to come over and have a nasal enema party?

  • Jacob S. says:

    A Neti Pot is for those that suffer from allergies. Basically it loosens and moves mucus to alleviate pain and remove any allergens that are in your nasal cavity.

  • Jo says:

    Hi, I just bought this unit after watching your video. The unit doesn’t come with the two quick connect elbows for IN and OUT. I will order them but I am not sure which one is it. Can you tell me with BFS-XXX (product number) from their website (under Fittings>>Elbows)? Thank you.

  • Bella says:

    I am planning my saltwater tank and I have watched a lot of your videos. You said that an RODI unit is very important and that everyone should have it. I noticed that you had a Buckeye RODI unit so I went on their website and I found this one,, is it okay?


  • AquaAddict says:

    I have used Air Water & Ice’s Typhoon III Extreme 150 for about 5 years. It is by far the best one I have used…the DI last about 3 times longer than other name brand DI resins and the membrane still hasn’t gone bad! I sent a email at 10:30 pm on a friday night (I forgot to turn the fast flush back to normal operations)…but they still responded in less than a hour!!! I love my RODI system and I would never give my little babies anything else. Get a RODI !!!

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