55 Gallon Evaporative Cooling Community Tank

Discussion in 'Freshwater Aquarium Builds' started by McFly, Aug 5, 2015.

  1. McFlyValued MemberMember


    This is my 55 gallon community tank. I decided to go back to my Aquarist roots after taking down my Mbuna Cichlid set up to install new flooring.

    Biggest hurdle for this is water temperature. Here in steamy Florida, it's difficult to keep water temps down in the mid 70's when the house goes up to 83* during the day while we're working. I decided to modify my traditional hood set up to accomodate an evaporative cooling system to keep water temps down.

    What I've done is remove the fluorescent top fixtures, then remove the glass the lights sat on. I replaced the glass with grating, then installed a cooling fan on each grate, that is controlled by a rheostat. The idea is to blow air down on the water to increase evaporation, causing water temperature reduction.

    Here's the particulars:

    55 Gallon tank
    Cascade 700 canister Filter
    Whisper Air Pump 60
    100w Heater
    (2) Cooling Fans with speed controllers
    (2) 17 inch LED Clip on Light strips
    Clear acrylic

    Here's the left side of the tank cover viewed from the top:

    Directing the filter wand to agitate the surface of the water under the grating does create some cooling without the fans. With the fans running on low, the water temperature can be dropped to 75* with the room air temps between 78 and 83*. The heater prevents water temps dropping below 75*. I'm currently working on a temp switch to control the fans, so I can rely less on the heater to regulate tempurature.

    Water stays within 1* variance (average about 6/10 of a degree). Evaporation is about a 1/3 gallon a day. This has worked out great so far, and I'm pleased as punch with the end result. Fish seem happy.... I'm happy. It's a win, win!

    Last edited by a moderator: Nov 23, 2018
  2. Et tuValued MemberMember

    Good diy build. I live in Las Vegas where if the temp goes down to 103* it's called a cooling trend! I keep my tanks cooled with fans also.

  3. Anders247Fishlore LegendMember

    Nice tank!

  4. DadioWell Known MemberMember

    While I love what you've achieved and admire your forward thinking my only point I can see is the cost/waste factor using this method if your in an area where you pay for water use.

    The very 1st thing you did that made a major difference was getting rid of the fluo lights. LEDs get rid of the hz, heat and are far more energy efficient. Fluo's alone can increase temp 5 to even as high as 1 degrees depending on if encased or free air and distance to surface. Increasing surface agitation is another key point you picked up on which has a multitude of beneficial factors. Proper circulation is also another key factor in which all of the above are great steps.

    I had a some what similar issue with my custom cedar enclosure. I installed a 90 cm fan(old computer) to go across the inner top of the case creating a breeze effect and not direct to the water. My evap loss is about 1.5 gallons per week where before it was closer to 5. Very dry where I am for the most part. I used LED from the start of my 55g build using a 48inch current unit that threw off enough ambient heat to increase tank temp 3 degrees keeping tank temp at 80.9 F where as now using the Aquaray GroBeam the offshoot temp is 1 degree and tank temp now at a happy 77.5 day and 76.5 night.
  5. McFlyValued MemberMember

    I appreciate your input Dadio. I've found the fans only need to run at very low speeds, but are necessary to maintain temperature. I think in the cooler months I may be able to remove them and reduce evaporation a bit. When I compare the 'cost' of water to the cost of a chiller system, I'll be far better off. Chillers are far more expensive to buy/run, especially a good one.

    Nice to hear I'm pointed in the right direction! ;)
  6. KwigWell Known MemberMember

    I'm in Las Vegas too. But my family members like to keep the dang house freezing cold so I still need a heater, haha.
    What kills me here is how dry it is. When I lived in Florida I never had to top off my tropical tanks. Here I have to top off once in between my weekly water changes and then you have to fight with that ring of hard water grossness.

    I used evaporative cooling on a 20 gallon long tank that held juvenile axolotls when I lived in Florida. Very effective. Much cheaper than a chiller.
  7. JsigmoWell Known MemberMember

    Being a control system and electronics nut, I'd rig up a system to throttle the speeds of the fans to get the temperature down to the upper limit I want, and hold it there. Then, with a bit of "gap" set a lower setpoint where the heater would kick on.

    That way you never have the heater "fighting" the cooling fans.

    But what you've done is actually done by some large manufacturers of laboratory incubators. They make them from standard off-the-shelf freezers, and set them up so the refrigeration compressor runs 24/7. Then they control the actual temperature by operating the defrost heater as needed with a PID controller.

    It's crude, but effective. The problems are that it wastes enormous amounts of electricity, and adds a lot of heat to the laboratory, since you have the heat of the compressor system running constantly plus the heat of the heating element all being expelled into the lab constantly.

    One thing I would worry about if I was controlling the fans would be the effect of moisture on the fans. While they're running, there is likely no problem. But when they'd be off, they might experience high humidity, and maybe condensation. So I might try to find a way for the fans to be outside of the high humidity area, and use some pvc pipe or the like to make ducts to carry the air to the water surface.

    Hmmm. More fun aquarium related projects! :)
  8. JsigmoWell Known MemberMember

    You guys should also probably be using distilled, or at least RO water for the top-offs so you don't concentrate minerals in the aquarium water.
  9. McFlyValued MemberMember

    You must have that ESPN thing,,, reading my mind like that. Visual aesthetics are important, as the tank is in the living room... BUT I was thinking about at least raising the fans an inch or two, and putting slats below them to spread air outwards, while limiting moisture rising when the fans are low/off. I'm handy with acrylic/plexiglass, and I think I can do it... maybe so far as to adjust the air direction a bit.

    The Controller for the fans is available on Flea Bay for under $20. No speed control, but it will turn them on when the water temp reaches a preset temp. The variance is high though, 4* I think.

    So the build goes on.... but does it ever really end though?
  10. McFlyValued MemberMember

    I'm thinking about gutting the fluorescent fixtures for the hood... heh heh. I could then mount the fans on the side of hood, and deflect the air down with a few simple fins. The hoods will block the grated area which is key to evaporation, but seeing as I'm destroying them, making new vents somewhere in them wouldn't be difficult.

    This is probably the most viable way to make the set-up visually appealing. Back to the drawing board!
  11. JsigmoWell Known MemberMember

    Finding ways to combine good effective performance with good looks is a real artform, I think.

    Industrial design is a fascinating field. There are some great examples that really seem to me to be right up there with any "Fine Art".

    Finding ways to deal with all of the functional issues while also addressing the aesthetic impact is a heck of an achievement in a product. I often blow off the aesthetic end of things, and don't mind being able to directly see the mechanics of a system. There's a certain beauty in that, at times.

    But I also appreciate a system that manages to conceal the innards or use them artistically.

    If you are interested, I can draw up a schematic or even build you a controller to run your heater and the fans.

    I've designed a number of these sorts of things, usually for laboratory environmental rooms or chambers where temperatures and/or humidities needed to be kept within a small window.

    Also, there was a thread on here where a guy used the Peltier module and fan from one of those portable coolers that plug into a car cigarette lighter as a chiller for his aquarium. He mounted the "cold side" heatsink so that the fins protruded down into the water in his HOB filter, while the "hot side" and fan were aimed upwards above the filter.

    This eliminates the evaporation issue, and is still pretty cheap to build.

    I never found out how this worked long-term, but it was a great concept, and seemed very practical.
  12. McFlyValued MemberMember

    Now the wheels have finally started turning, Seeing as I was just going to toss the hood lighting fixtures anyway, I decided to hack them up into little pieces first!! The fan set up WILL work afterall. Here's what I've come up with:

    Both fans will be at the center of the tank, and blow towards the ends of the tank. I can mount the fans to blow straight down, and redirect the air under the hood itself, then cut the top of the hood out, and install grating there to allow for evaporation.

    So here's the 1st fan hole cutout:


    And that fan installed in hood:


    Next is the deflector (acrylic) and mounting it under the fan. This will provide some protection for the fan from water as well as redirecting air to blow across the water's surface. This set up has met the approval of the CDO (Chief Decorative Officer) and will probably improve overall efficiency of the cooling. :)
    Last edited by a moderator: Nov 23, 2018
  13. McFlyValued MemberMember

    Here's the difference in visual aesthetic, though I will have to do the grating 'right'. I may actually
    go with black screening to make it less gawdy.

    Last edited by a moderator: Nov 23, 2018
  14. BDpupsWell Known MemberMember

    Do you not use the air conditioner in your home?
  15. McFlyValued MemberMember

    Yes I do, but during the day it's set to 83* and it's at 78* when we're home... the water isn't
    likely to get too far below 78*.... Air conditioning the entire house to 72* in Fla. borders on insane if you're paying the electric bill.

    .... A good example of the need for these fans and this system is the rise water temps from 77.4 to 81.6 with the fans off for 5 hours.
    Last edited: Aug 9, 2015
  16. BDpupsWell Known MemberMember

    good luck with that....
  17. McFlyValued MemberMember

    So, I went and spent $8.00 on Stainless steel hardware to mount the fans and air diverters. I've also cut the acrylic and pieced together the diverters to push the air across the water instead of straight down. These will also act as protection for the fans from splash and water condensation hitting them directly. The glue needs several hours to completely cure, so when they're dry I'll post pics of what they look like.

    All that's left is to cut the tops of the old light hoods and put in some grating for ventilation. I'm even going to paint them black this time, so they'll match.

    So far, this hood 're-purposing' project has been a lot of fun, tinkering and such. Added cost has been $8.00, still far off from the cost of buying/running a chiller. :;hf
  18. McFlyValued MemberMember

    The metamorphosis continues:

    I've managed to cut the covers for grating and cut the grating and paint it. Here's the
    almost finished product (still some touch-up work) :


    The acrylic diverters are also ready for install, and look like this:


    The final assembly is next. The fan mounting hardware will support the diverter, as well as a screw from the back. Initial test shows good air flow with the diverter, I'm hoping that doesn't change....
    Last edited by a moderator: Nov 23, 2018
  19. McFlyValued MemberMember

    Here's the pretty much finished product (for one side) :

    Here's the underside, with the diverter mounted so the air is pushed across the surface of the water.


    Here's what it looks like from the top:


    The design works well, and very little air is lost (it goes through the diverter mostly). I'll probably put a bit of split old air hose around the base of the hood to isolate it from the rest of the hood, making it even more quiet.

    The left side is still under construction but will pretty much mirror the right side. I'm hoping the grating on top, which is a bit smaller will allow for adequate evaporation. I didn't want to make the grate much bigger because it might compromise the rigidity of the hood itself.

    Next update should be the whole gamut installed and running on the tank...
    Last edited by a moderator: Nov 23, 2018
  20. Et tuValued MemberMember

    Looks good, the black screen + flush mounted fans, kick it up a notch. Necessity is the mother of all invention.

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