A rare situation

Biocube 14 hood modification – new fans

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Heigh ho internet! I’ve returned to blogging after a year and a day and then fourteen more days away from it all. Various things have happened in the interim but what’s pertinent at the moment is that last November I got a Biocube 14 – an all-in-one aquarium in which I’ve revived the saltwater aquaria I used to keep in college. It has some modifications (because I can’t leave anything alone) and today I’m going to share the process of retrofitting the hood on the Biocube to replace the godawful stock fans with a little more “oomph.”

Why replace the stock fans? The bearings on the fans that come integrated into the hood are pretty lousy. Users frequently report that they start making grinding noises and fail to turn. Unfortunately my tank was no exception. The Biocubes also have a problem with condensation forming on the inside of the hood. Normally this is no problem but whenever the lid gets raised a lot of water runs down the back which isn’t good for the wiring or the carpet. I found a couple of guides showing how others had done this retrofit and I combined their approaches.

Step one: remove the hood. The Biocube’s hood has two plastic hinges which are held together by a pin. Slip a screwdriver into one end and gently pry.

The lid is off! Check out all that condensation…

Step two: remove the plastic lid and (carefully) remove the bulbs.

Step three: remove the metal covering the hood electronics.

Now here was where I was hoping to save some work. My plan was to put four new fans in the hood where previously there were only two. I’d have liked to wire them into the existing power supply and not have to run a new one – one less plug to deal with after all – but no dice. Not only is there not nearly enough amperage (my new fans draw 110 mA each and this transformer only puts out 150 total) but it’s AC instead of DC. Oh well.

New fan on the left, old fan on the right. The new ones are Sunon MagLev fans which are reputed to have much nicer bearings.

Step four: remove the old fans.

Step five, optional: hack away the airflow restricting interior fins underneath the stock fans. I did this using a Dremel with a flexible extension – there isn’t a lot of room going on in here.

Step five continued: do the same with the airflow restrictors along the back.

Step six: drill intakes and mounting holes for two fans in the back both blowing inward. This is a slightly harder modification than just replacing the stock fans but it is worth it. These two fans have basically eliminated the condensation problem. It comes at a cost: evaporation goes way way up. I’d recommend an auto-topoff if you are going to go the four-fan route.

A twelve-hole pattern drilled for the intakes of rear fans plus four for mounting. I used nylon screws so there’d be no chance of rusting over time.

All four fans mounted up.

Step seven: wiring up the fans. I used a charger from an old phone which puts out 700 mA at 5VDC. The Sunon fans are rated for 12V so running them at 5 is undervolting them rather a lot but that’s okay. Despite having good bearings they aren’t particularly quiet. I tried running them flat-out at 12V and it sounded like a jet engine was taking off in my living room. 5V seems a good compromise for air movement versus noise.

All four red fan wires tied to the positive output of the power supply, all four black wires tied to the negative output. Seal it up with some electrical tape and away we go.

And that’s it! Replace the metal electronics cover, the bulbs, and the plastic light cover and plug it all in.


  • The hood is much quieter after having replaced the stock fans.
  • Condensation is a thing of the past.


  • The hood isn’t silent by a long shot…but that wasn’t really the point.
  • The general temperature of the tank is lower than it was with only two fans but it’s still very warm. Eventually – like in a couple of weeks – the stock lighting needs to come out and get replaced with LEDs lest my tank come to a slow boil over the summer.

Written by Chris

April 1st, 2012 at 9:39 pm

Posted in General

One Response to 'Biocube 14 hood modification – new fans'

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  1. What? Sammis use a dremel tool? I’m stunned. STUNNED, I say!

    Russ Graves

    8 Apr 12 at 4:22 pm

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