I have been doing a lot of day dreaming about how I will set up the ADA tank I will be getting, sometime in the dim future. One thing I want is an open top, rimless tank, with the light fixture suspended above the tank. But, I'm not entirely happy with the appearance or the convenience of fixtures hung by cables or chains.

My goals are:
The fixture hangs over the tank.
It is easy to raise out of the way for tank maintenance.
The power cord is very unobtrusive.
There is minimal light spillage.

I looked first at using drawer slides as the basis for holding the fixture up, but I couldn't work out a good way to both get working clearance and keep the light shining into the tank, not my eyes, when doing maintenance.

That led me to consider a parallelogram linkage. Here is the concept:


I was excited enough by the concept that I decided to make a fixture like this for my existing 45 gallon tank. Here is the basic structure I made for that, mounted on a board simulating the wall:

I finished the "hood", which is made of 1/4" hardboard (MDF), by veneering it with oak to match my tank.


Inside, I used aluminized mylar to make reflector wings of the front and back of the hood to eliminate spillover there:


Finally, today I mounted the fixture, after a real battle with my sluggish brain and the open topped full tank in the way.


In the raised position, for maintenance, look at the amount of room it allows:


The lights are AH Supply 55 watt kits, with GE 9325K bulbs, which makes for a terrible photo color balance, but looks great for the tank.


I see this design as just one more good way to "hang" a light fixture over an open topped tank. It has advantages, and for some it probably has disadvantages.

Vaughn,

Very very nice and a great idea.....

Does the hood stay put in any position, or just at the high vertical and horizontal points?

How long did it take and can you list the materials required?

Nice tank BTW and I absolutely love the group of Anubias up front.....is that lace windelov directly behind it?


Thanks,

Thank you Gerry. The "anubias" in front are actually Lobelia cardinalis small form, a really nice plant, and behind them on the left is windelov as you noted. The tank is now badly overgrown, but I keep trimming off the willow leaf hygro in back, just to keep it looking about as it does. This is how I wanted it to look, even though I know it needs a "haircut" desparately.

The hood only stays down, by the links jamming together, or up by two barrel bolts stopping the links from swinging down. It could be designed in several iterations - with variable length links, with friction stops to keep it at any positiion, for example.

Materials are:
The bracket that attaches to the wall is made of a length of poplar 1 x 3, screwed and glued together on the ends. With two 1 1/2" long barrel bolts, one on each end.
The links are a 4 foot long piece of 1/2" x 1/8" weldable steel, cut into 4 equal lengths. (from Ace Hardware)
The light fixture "hood" is made of a 2' x 4' "handy panel" of 1/4" hard board, which is a MDF type material.
It is veneered with white oak veneer from Woodcraft - a package of 12 square feet. It is glued on with water based contact cement.
It cost a total (excluding the oak veneer project) of about $40.

My initial plan was to make the hood out of aluminum sheet, but my enthusiasm for the design got to be too great for me to wait while I learned how to best make a sheet metal hood. I still think a sheet aluminum hood is the best design.

For some more detail see: http://www.aquaticplantcentral.com/f...t-fixture.html

Yes, very nice hood!

Regards,

Tom Barr

Very nice!

I have found this cantilevered, parallelogram linkage support to work extremely well for me, so I designed a "kit" that will work for many different hoods or fixtures. You can see what it looks like and download a pdf on how to make it at: http://www.oregonaquadesign.com/hopp...veredlight.htm