Mr. Saltwater Tank TV Friday AM Quick Tip: This Little Piece is Worth It’s Weight In Gold


Sometimes the low-tech pieces of equipment can prevent the biggest disasters. I still cannot figure out why everyone doesn’t have one of these on their RODI system.

Browse the Store! Questions?

Comments for this article (16)

  • when making RO water should the water be stored constantly moving or just stored in tank?

  • trevoseal says:

    Hi Mark
    Should suggest that when using auto shut off, put a piece of styrofoam under float and attach with rubber bands so that if the float fails you will not have a flood. It worked for me.

  • eric…RODI water can just be stored. It doesn’t need to be agitated like saltwater

  • Rich says:

    wow that styrofoam suggestion is on of the best yet as I have had them over flows myself thanks for that tip

  • John Vandersloot says:

    Agreed, auto shut off float vavles are great and a must have.
    Problem is they have failure modes, which may or may not be easy to recognize by the average reefer (until it happens and you say to yourself man why did I not see that coming)
    I am lucky enough to afford a apex so my float valves are backed up with a secondary float valve (higher up in my RODI container) and a floor leak sensor both of which will send me a email and alarm if they are triggered.
    When setting up a system think about potential failure modes of what you are doing and back up or even double back up if poissible. Every process you set up will have failure modes!
    Next think about prevention and detection. Prevention is best but dectection may be only thing available (as is the case with cheap float valaves). The quicker the detection and reaction the better
    Remember having or not have a controller is not excuse for not being creative.
    One of my good friends does not have a controller and installed a drip pan under his RODI unit with a drain he rigged to go into his crawl space.
    He checks this pan on a weekly basis in his reefing schedule to see if it is wet. A little water in the crawl space is easier to deal with than on the carpet
    Happy reefing. John Vandersloot

  • trevoseal..send me a pic of yours and I’ll use it as a Friday AM QT

  • Ron says:

    While I did get an overflow float valve, I did not hook it up yet. I do have my RODI barrel in one side of my slop sink, so even when it does overflow, it goes right down the drain. The float valve for me is to not waste water. Need to get that installed.
    Mark the tips and videos are all so informative, thanks.

  • Jeremy Carter says:

    Mark, great tip! Is there a particular float valve system you reccomend for your RODI tank?

  • aaron jones says:

    some of us have to watch these at work, haha any chance for subtitles?

  • brice ruppert says:

    Some of us have to watch on there phones with no wifi. I can’t ever get a video to load. A typed up summery even the briefest of write ups would be so helpful on my end.

  • Geraud says:

    Note that in general, I would avoid setting an “ATO of the ATO” fully automated without having *multiple* fail safe mechanisms.

    Aka, use a float valve as a security in case you forget about your RO/DI running while replenishing your ATO container, but do not let it run constantly thinking “hey that float valve will handle problems”. A friend of mine had a valve fail, and he was out for the week end. When he came back on Monday his neighbor was not too happy… even if the water that ruined is apartment was very clean.

  • David Stuber says:

    I like the idea of a float valve but I put a timer on the water supply instead. Works great.

  • John M says:

    I check your float valves with piece of styrofoam under float and attach with rubber bands so that if the float fails you will not have a flood. That is okay but some float valves how they are made will brake off the stem. I know I had some do that to much pressure and some split were it screws in the stem. I only saying this to be helpful as it happen to me.

  • Nikolaus says:

    I would never rely on a float. I physically shut my water off, relying on an autoshutoff I think is more dangerous than paying attention to what you are doing.

  • Pierre Bouic says:

    The one fault in common with all these so called fail safes is the human facture, if you know what the maximum rate your RODI will process water at is then calculate a volume of water with a small safety window for any error. It cannot pump more the manufacturers specs so say 50 gallons per 12hrs, then set your phone to alarm or timer mode. But again you have to remember this. Last week I forgot to set my timer but because I pump RODI at night I leave a light on in the tank room hallway which alerted me that I was to the fact I’d left it running. but it wasn’t a huge problem only missed by around 2-3 gallons, so out with the mop and fan to dry the floor tiles. I think the drip tray option would work best in my situation.

  • The Kippax Crew says:

    For a long time I had my RODI run into a a large rubbermaid garbage bin with a very simple replacement float desighned for a home humidifyer. It had an open bottom that would trap air in it when the water was coming up so it would never crack and flood causing a failure. In an attempt to lower the evaporation and thus the humidity in the house I finally purchased a proper 25 gallon sealed storage tank with an air bladder inside, this way the RO unit would run as long as it takes to fill the tank and then it just shuts off when the tank is full there is no way that it can fail since it never depends on a float of any time. When I need the water I just turn on a tap that is Teed in between the RO unit and the storage tank and the flow reverses out of the tank and into a small 5 gallon tank that is connected to my sump with the same type of humidifyer float to slowly drip in the water as needed. Filling the small tank only takes 5 min with the 40 PSI bladder in the tank pushing out the water. In 8 years this float has never failed and if it should it would only be an extra 5 gallons of water in my 150 gallon tank that would not throw my salinity off too much.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.