Can you suggest a reliable, long-lived fan to ventilate a hood area?

Discussion in 'General Reef Discussion' started by capman, Oct 18, 2017.

  1. capman

    capman I contributed!
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    Call me old fashioned, but, I've decided to include some metal halides in my new systems.

    There will be two (along with some other lighting) over the new 6' x 4' x 2' high tank.

    The area above this tank will be enclosed on the front and sides (with sliding panels), but open in the back - this area will be 30" high.

    This will actually be my first time using metal halides inside an enclosure (all of my metal halides have been open air before), and I'm thinking I'm going to want some air circulation in that space to move heat out a bit better.

    I can get inexpensive fans, say, at Menards, and BRS sells a clip-on fan, but I worry about long term safety with such fans when run continuously - it seems such fans sort of wear out quickly.

    Can anyone suggest some sort of fan to blow air into this space (from the rear) that would be simple to set up and that would be a bit higher quality and long lasting?

    Or... maybe I just should get some sort of inexpensive clip on fan and plan to replace it yearly?
     
  2. nubbs

    nubbs Junior Member
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    I would get something that is rated for "continuous duty" them find out if it is rated for the heat / max temp and humidity of the work environment.

    The pic meets the continuous duty part, not sure about the temp and humidity.

    [​IMG]

    Sent from my SM-G900V using Tapatalk
     
  3. Riley

    Riley I contributed!
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    Ditto on the continuous duty. You can look for the kind used in grow lights, you know, for growing "herbs"
     
  4. LoganLaBonne

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    I plan on running these to ventilate my new stand. They are very quite and say to have a lifespan of 67,000 hours (2,791 days or 7.6 years).

     
  5. OP
    capman

    capman I contributed!
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    Does anyone know how loud these sorts of fans tend to be?
     
  6. RSnodgrass

    RSnodgrass TCMAS President
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    Capman, this may not be the kind of fans you'd use over a bath fan and temp sensor but they serve a purpose.
    I'd consider a main fan that is always on (at least with lights) and a back up wired through a standard thermostat if the air temp is too hot... and/or use an apex when the water gets too hot.

    I can speak to computer fans, I've used them in multiples (7) successfully for years and never had one fail but there are a couple tips which may apply in general.

    Air Flow:

    Be sure to convert all parameters to CFM (the most common). For computer fans that are standard 3-4" will max out around 30-50 CFM and still be quite enough. Larger diameter fans can move alot more air for the same noise profile which is important as 30 CFM by itself isn't much.
    Noise:
    Personal opinion but 20-25 db(A) is still really quite and not likely to hear anything. 17 db(A) is non existent and you'll possibly wonder why you didn't go louder to get more air flow.

    My current set up is modeled after my last.
    Hood:
    I have 6 fans in the hood centered above each light to prevent dead spots. The fans blow air out the top and pull air from gaps in the hood lower down so they don't suck heat off the ceiling... which is serious problem in the winter, just stand on a ladder and you know it. They will also accumulate dust and having them blow out allows dust bunnies to clear naturally away from the tank. I could have went with fewer, larger diameter, fans from the same company but ~32CFM x 6 is plenty and they are virtually silent to the ear at 18 db(A). Again, in your case you may consider using computer fans but have them separated so one set runs all the time and a second set when the air temp is too hot.
    Fans Used - Searching on Newegg is usually easier then Amazon. Arctic is another brand I've been very happy with.

    Sump:
    I also have four larger 6" fans in the sump because it's enclosed. I have two push air in and two pull air out... the two pulling air out are always on but the two pushing air in only turn on as temperature increases on the water. These move ~60 CFM each. You would think two going in and two out is a waste but I find that air flow across the full cabinet simply doesn't happen with vigor and leaves alot of dead spots.
    I'll edit later with the link.

    Emergency:
    Lastly I have two 6" fans that buck at 120 CFM each and are louder. These are my emergency fans and only turn on if temp goes even higher yet. This was a result of some basic science education from D.G. so I've got these pointed directly at the water for evaporation in the sump. I picked high volume and loud fans to both move air but also easily alert me that they are having to run... no computer needed, just ears.
    I'll edit later with the link.

    Other Items:
    I power the fans with THIS. Simply divide the amperage of the power strip with the amperage of a single fan and you'll know how many it can power.
    I spit the power to various fans with something like THIS or THIS
    I wire them together with THIS.
    If you have fans that are too loud or too fast you can either wire more fans to the same power supply (limiting the power per fan available) or add something like THIS. It worked better then the fancy ones I've used in the past.


    *** If you go with a bath fan consider PANASONIC! They are very quite compared to the stuff at Menards. THIS is the one I have but they of course have different size options.
     
  7. OP
    capman

    capman I contributed!
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    Thanks for all the suggestions and information!

    The more I think about this though, the more I like the sort of continuous duty inline fans that nubbs suggested. Interestingly, starting from scratch and using his suggestion to search for "continuous duty" fans, and looking at a variety of rather different sorts of options, I ended up circling back to some fan designs that looked appealing, and then I looked back at nubbs' post and realized I'd chosen something very much like what he had suggested!

    One thing I like about these is that they are, literally, plug and play in that they come pre-wired to plug into a standard electrical outlet (I really don't want to be messing around with electrical wiring).

    And the other thing is that they could be mounted semi-remotely in my aquarium room and air could be directed into the areas above the tanks with the lights fairly easily using 4" flexible ductwork. Perhaps I'm being naive, but it just seems I'll just need to be sort of flushing out the hot air above the tank using metal halides, and pretty much any way of blowing air into this space will likely be enough (it will be a big space).

    And all this thinking about heat from metal halides in tight spaces is making me reconsider the lighting of my seagrass tank. I think I'm might start out by giving really bright LED's a try. If that doesn't work I can always switch to metal halides, but given that the space over this tank is going to be smaller heat might be more difficult to deal with
     

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