Calling all woodworkers: questions about framing to support 300lb fish tank

I’m getting a 30 gallon fish tank and intend to build a stand for it. The tank is 36"w x 12"d x 16"h and the stand will be 36.5" w x 12.5"d x 33"h. The tank will be approx 300 lbs when full.

The reason I’m building a stand is because the stands offered at the giant aquarium store in my town are crappy AND expensive. Most are made of 1/2" coated particle board, and they’re all around 7" shorter in height than I would like.

I’ve looked online and most sites I find with DIY recommendations are for larger tanks and all suggest framing with 2 x 4s. Looking at the crappy stands in the store make me think this may be weighty overkill.

Would I be OK framing with 2 x 2s? Do I need to consider a bigger foot for stability given the higher height I desire?

Any input would be most appreciated!

If you are going DIY, I would build it out of 2x4s, no question. A sturdy box with bracing etc will do fine. 2x2s might carry the weight, but I bet would be wobbly. Make it rigid. You can cover it with anything: wood, fabric, nothing, whatever.

Another thing I’ve done is buy a cool old dresser at a yard sale. Paint it (I used semi-gloss black) and park the aquarium on top. You have a whole lot of storage underneath the tank now.

Use 2x4s. Make sure there is cross bracing on the legs, and you don’t need to make the “feet” any bigger.

2x2s might be OK for a chair, which is much less than 3ft wide. Be sure the 2x4s on the top part have the “4” dimension vertical. :wink:

I would make an enclosed structure, 2x4s would work for framing, but I’d put 1/2 inch or thicker plywood walls on it for strength. When I kept fish I used metal stands, and heavy metal carts made from old disk drives cabinets. I did have a 100 gallon tank on a cabinet made of oak, and reinforced the interior in the middle with some heavy hardwood planks standing vertically.

The problem with 2x4s is that they can split and warp over time. And fasteners you use have the potential to come loose over time as the wood dries out. And they will look kind of ugly.

Good idea about the plywood.

They hold up your house OK. They should be fine for a fish tank. But yes, cover them. They are ugly.

I would strongly urge you to buy metal strapping and secure the fish tank stand to a stud in the wall. Or you can easily screw through your stands frame and into a wall stud. Either way it won’t topple over.

There’s been several recent deaths of children from furniture falling on them. It’s often a tv on a dresser or chest of drawers that does it.

A fish tank is much heavier.
April 2012
http://abclocal.go.com/ktrk/story?section=news/local&id=8607175
Feb, 2012

Jan 2012

I have such a thing. It is a hefty metal shelving from Lowe’s covered with cosmetic woodworking for appearances. The woodwork is fine veneered plywood over a light frame.

I would use 2x4s and have plenty of internal bracing before sheathing the outsides with plywood. You don’t want to end up with any wobble, 300lbs is significant weight.

For the outsides, I would use a stain grade finish or apply a veneer, you want it to look nice.

I see this in a frame I’m looking at online. Why is that necessary?

I assume cross-bracing is that metal, x-shaped thing you screw across the back (or sides) of a structure. Yes?

2x2s will certainly be able to carry the weight, but I would consider something to give them a bigger foot. The easiest way to do that might simply be to set the whole thing on a sheet of plywood and secure all the 2x2s to the same sheet of ply. Consider running more 2x2 between the bottoms of the feet, and if you’re covering the outside, then you can put some cross-braces on the inside. They’re ugly, but there’s no better way to eliminate wobble.

Also, if you’re worried about the weight and still want 2x2s, use six legs instead of 4. That’ll help with your weight distribution. 1x6s on the top should be plenty strong for so short a span as that.

ETA: Yes, cross-braces are the x-shaped thing. Proper cross-bracing makes it nigh impossible to have your whole stand collapse to one side or the other.

2x2 might support the weight if you used enough of them. they would all need to be braced (could have each piece fastened to the skin).

2x4 is large enough to put multiple screws into so that it braces itself.

I’m sure you could get away with using 2x2’s and be fine. One nice thing about 2x2’s is that you can temporarily fasten 4 of them side by side and cut them in one fell swoop on a sliding miter saw, getting 4 perfectly identical pieces. This will help create a square and true box which will get you the strongest possible finished product. Once it is generally assembled, set the saw at 45degrees and cut corner braces from offcuts. I’d get everything together and then loosen the screws and inject wood glue into the joints and retighten, making stronger joints. Skin the frame with some kind of ply, that will make it more rigid and stronger. I’d use nice looking veneered luan or whatever looked nice and was cheap that day, but no pegboard or particle board as they are easily destroyed without much water.

I have a similarly constructed stand for my 40 breeder(18x36x16) with a 20 gal sump and it has been set up for years.

Why would you even consider using 2 x 2s when an eight-foot 2 x 4 is under three dollars? It’s actually more relevant how you’re going to arrange the wood than what wood you use, anyway. I think I’d feel better about this whole thing if you found a woodworking-savvy friend with some tools to give you a hand.

Bolding mine - this, a thousand times THIS.
Cross bracing is the key to making this thing stand up and it’s the thing most often overlooked.

A single 2x2 can easily support 300 lbs of vertical load. You will have 4 of them.
The issue is “racking” or shear force - you need to brace the box diagonally, or use a plywood skin to remove any possibility that a side will change from a rectangle into a parallelogram. When your stand is done, you should be able to brace the bottom edge and push with all your strength on the opposite top edge, and not move the sides out of true. If so, your stand will support the tank with no issues (although tying it to the wall isn’t a bad idea, as mentioned above).

Thanks for advice, all. I’m no structural engineer to be sure, but just knowing that I can ease up on my OCD about safety is making this so much better. And yes, I will secure it to the wall- that’ll mollify the remaining niggling worries!

For stability, splay the legs outward at about a 5 degree angle. When attaching the stretcher to the lower legs, use a half lap dovetail joint to prevent the legs from ever pulling apart. If you decide to use 2X4 legs, taper each leg down to about 2" to provide a less then industrialized appearance.

Because weight on the wider dimension of lumber will cause it to flex. A 2x4 stood on edge is much stronger. This is why door and window headers are edgewise, and usually doubled.

We have a 125 gallon tank, and thisis the base my husband built - 2X4s and plywood with cherry on the 3 visible sides. It provides tons of storage and it’s an attractive addition to the room.

Even moreso with all thenew rock and fish. (OK, so this last one is gratuitous bragging…)

Yep, but door and window headers usually use 4x material, which is better than 2 2xs, not to mention being automatically flush with the 2x4 wall material (2 2xs = net 3" while a 4x = net 3 1/2").