Aquarium Stand without Center Braces?

[Slickbaby]

Hey guys,

I'm modifying an older stand to make it easier to work in. It is currently 96" x 18" x 36". The bottom frame is doubled up 2x4's and the top is a single 2x6 all the way around. 4x4's connect the top frame and the bottom frame. I currently have 4 4x4's on each side (4 in the front and 4 in the back, evenly spaced). The top frame is joisted together. There is 3/4" plywood on both the bottom and the top for the tank to sit on.

My question is do you think I could get away with only having 4 4x4's total? One in each corner? Would the 2x6's be able to support a 180gal tank + rock, lights, etc?

Sorry this is the best picture I could find....

 

[eastcoaster1]

I think you could get away with using 3 equally spaced 4x4s along each side - that would give you two large openings on either side of the center support.
I just don't think a 2x6 would provide enough support over a 96" span. You have to think about the fact that the 2x6s shouldn't bend at all. It's not like typical residential construction where a little flex on something like floor joist isn't a big deal.

 

[Slickbaby]

Hmm ok, cool. I guess I can give that a shot.

Thanx!

 

[barlav]

Similar to calculating a hot tub load for a deck you can do the following for a tank stand: (I used the calculators at bestdecksite.com for load deflections calculations. Very useful stuff there!!)

Assuming a 2000lb tank (includes tank weight, water, rocks, lighthing, etc..). Water for you tank would be no more than 1500lbs but more likely a few hundred less do to amount displaced by rocks, substrate etc.. Figured a max of 500-700lbs of weight taken up by tank itself, rocks, substrate etc.. Does this sound about right? Better to overestimate than under with things like this.

Stand area: 96"X18" = 12sqf
Psf: 2000/12 = 166.67 psf

A 96" 2X6 span for 166.67psf fails delection by over 300% using a L/480 deflection limit. In other words don't do it!!!

The same load with 3 supports (one in the middle along with the 2 corners) passes deflection (Actual= -.039 inches at 2 ft.)

Keep in mind this is for a deck which doesn't necessarily map to an aquarium stand. But, if the deck deflection fails the the aquarium stand will certainly fail.

So, I think you should be ok with 1 center support on each side for your tank.

Good luck!