Building a large aquarium stand... how to make it strong enough?

[Ryan Sparreboom]

I've been asked to build a stand for a friends new aquarium. It is a 150 gallon tank and the base is 48 1/4" by 24 1/4". When full of water, gravel, and rocks, it will weigh about 2000 lbs.

We joined brains to come up with a sturdy yet functional design, but I wanted to run it by you guys to see what you think. And also ask about materials to use. Hopefully I can explain the design so you understand.

Both the top and bottom will be 50 1/4" by 26 1/4", so that there is a 1" lip around the whole tank. I'm thinking I will use 3/4" Birch plywood. Should I double that up to make the top 1 1/2" thick? If so, can I use 3/4" of plywood on top of 3/4" of MDF to make up the 1 1/2"? There will be a 1 1/2" wide, 3/4" thick trim all around the top and bottom to hide the edges.

The stand needs to be 23" tall (including top and bottom). The verticle support between the top and bottom will be in the form of 4, 12" wide octoganal pillars, 20" tall, one in each corner, placed 1" from the edge of the top and bottom pieces. I plan on making the pillars from 3/4" plywood, cut at 22.5* on each edge and joined together with glue and biscuits to form the octagon. In addition to these 4 pillars, there will be one large elongated octoganal pillar in the middle of the stand. It will be wider than the other pillars (maybe 14"?) and extend from the front of the stand to the back. The front 3 sides of this octagon will open on hinges to allow access to this area, therefore the front 3 sides will NOT SUPPORT ANY WEIGHT. But the sides that extend to the back, as well as the back 3 sides, will. So as you can see, there will be at least a 14" space at the front of the stand that has no vertical support under it.

That is the basic design, I hope it makes sense. I tryed drawing it on Google sketchup but I don't really know how to use that program so I had no luck.

Questions:
- Does the design sound like it will be able to support 2000 lbs?
- With the top 1 1/2" thick, will the weight be distributed enough?
- Can I use 3/4" MDF under the 3/4" plywood to create the 1 1/2"?
- Do I glue and screw the 2 layers of the top and bottom together?
- Is 3/4" plywood a good choice to make the octoganal pillars?
- Am I forgetting any major considerations?

Thanks in advance.

[sascha gast]

http://www.cnidarianreef.com/

and just go to stand/canopy

that's how I built my 300 gallon saltwater.
stay away from MDF, MDF and water don't mix, don't care what anybody says.
Use good plywood, lots of Poly finish and use silicone in all corners inside the stand.
If you have a tank, you WILL get water on the floor and in the stand.

if you seal all corners, at least it's not soaking in the ply and swell it.

[Brian Backner]

A single layer of plywood for the tank support will be adequate as long it is well supported all along its outer edge. If you look at how an all glass aquarium is actually constructed, the tank only sits on its outer edges - the main "field" of the bottom glass panel is recessed upward by up to 1/2" - this is to protect it and to keep it from ever touching the supporting structure. Once filled, the bottom will actually bow down from all the weight of the water/gravel/rocks/etc. That recess is to allow for that movement and still keep it from contacting anything that could be a potential stress point and cause cracking or even failure.

Brian

[Wade Jacoby]

We have a 120 gallon aquarium which is around 6ft long and 1 and a half feet wide. I never paid much attention to how it was built till I saw your post so I opened up the base to have a look.

Only the edge is supported. They layed a piece of 1"x4" flat down on the cabinet top, which is nothing special, just 3/4 inch. There is an extra layer of 3/4 on both ends, but otherwise this thing is pretty much a standard cabinet.

As one of the posters mentioned, maybe the aquarium bottom shouldn't be touching anything. But, I think If I was building one, I'd put a piece of plywood a couple inches below the bottom to prevent ever hitting the bottom of that tank with a tool or whatever when you're under there working on something. I don't see how that could hurt anything.

P.S. Our's is a salt water setup. We're waiting for the last fish to die before we give it away and replace it with a pool table. :-)

[Walt Caza]

Hi Ryan,
I just wanted to echo that MDF is a poor choice in your application.
I am quite familiar with MDF, as I used to buy it a lift of 50 sheets at a time.

In any spanning situation, it sags over time. I have no confidence
that even layered with plywood it wood contribute appreciable structural
rigidity. This stand project deals with uncommonly extreme weight for a
piece of furniture.
No time to be cheap with materials, as failure would get nasty right quick.
Try to name any other piece of household furniture that carries even
half that much weight. Compounded by the ravages of time...yikes!
Good luck with your project,
Walt

ps sascha, your tank and website are just gorgeous...great work!

[J. Z. Guest]

Ryan - Do a good search of the Dowelmax threads. I don't remember which one or where, but one SMCer built his out of several different hardwoods, including Purpleheart and Doweled it together. It was extremely well done. (He posted pix) Maybe he will chime in soon?

[Sean Troy]

If you look at the pre built stands at aquarium stores, they are built with mostly 2x4's. Even for the 200-300 gallon aquariums. Wood on the verticle can withstand enormous loads when put together correctly.

[Robert Mayer]

Ryan - Do a good search of the Dowelmax threads. I don't remember which one or where, but one SMCer built his out of several different hardwoods, including Purpleheart and Doweled it together. It was extremely well done. (He posted pix) Maybe he will chime in soon?

That was me! Its a 125 gallon tank and is really way overbuilt. My wife came up with the design. The bottom pic was what it looked like halfway through.

The entire thing was built with my dowelmax. Around 200 of them are in it.

[Paul Johnstone]

I've been asked to build a stand for a friends new aquarium. It is a 150 gallon tank and the base is 48 1/4" by 24 1/4". When full of water, gravel, and rocks, it will weigh about 2000 lbs.

Is the tank glass or acrylic?
Acrylic tanks need full support on the bottom.
Most glass tanks are designed to support the wieght on the corners, although when you get to that size, I'm not 100% sure.

In any event, avoid using MDF. I am pretty sure the structure integrity is compromised when it gets wet. And the stand will get wet sometimes.

I have a 180 gallon aquarium and am in the process of building a stand for a 300 gallon.. One thing to keep in mind is that when you go over 125 gallons, you also have to worry about the floor sagging.. I am not an expert on this part, but I would not put this tank on a second floor. Basement is great.. 1st floor is doable, but it recommmended that you place it near an exterior wall, perpendicular to the joists, and/or near the big beam in the middle of the house that supports the floor... Now I say all that, but I've put a stand with two 75 gallon tanks stacked on top of each other somewhere that ignored those rules.

I would discourage you building the design with four octagon posts. It might work, but I'd prefer to go with a tried and proven design.. I'd build a stand that size out of 3/4 plywood, with a solid wood face frame. I go a little overkill and use 3/4 plywood for the back as well.

If possible, make the base thicker, as it helps spread out the pressure between the tank and the floor. That's another hint they give, although I'm not sure it's crucial if you make all four sides out of 3/4" material..

I also use pocket screws inside the stand to help reinforce the carcass.. I know, in theory a properly glued case would be fine, but the extra insurance makes me sleep better.

Also, I recommend a poly finish, because water will get spilled on it.


Edit: One final suggestion.. It probably isn't necessary, but I put a brace in the middle of the cabinet (joining the front face frame and back), to help prevent bowing of the stand. It doesn't have to go all the way to the floor.. I put glue two 3/4" plywood strips about 2-3" wide and fit them in.. Again, better to overbuild.. The 2 x 4 stand idea works well too.. but if you build a regular cabinet, you can put in drawers for the nets, chemicals, etc. That is really appreciated.. One last thing.. for my 300 gallon stand, I am using 2" oak for the front and back.. as this is uncharted area for me.. I also reinforced the floor.. I mentioned that tank earlier, so I wanted to clarify that it is another step up from my 180 as far as weight goes..

[Brent Smith]

Hi Ryan,

First let me say that I am in the aquarium business and have built dozens, if not more, of aquarium cabinets and wall units.

You've been given some good info here. First off, MDF is not a viable choice for this application. Even ply is my second choice when building for aquariums. Only the edges of the aquarium, especially on the ends need be supported. Given the length of this aquarium I would divide the length with a stile front and back, you can design any cupboards or drawers around that. The main requirement is that all edges be on the same plane and level side to side and front to back. This is best accomplished at installation with hardwood shims under the bottom of the cabinet. Regardless of how square you build the cabinet there is always the floor to contend with.

[Bruce Page]

Ryan, I built a stand for my 110 gal setup with very similar construction to what Sascha linked to. It’s all red oak construction and has been in use for about 10 years.

[Dennis Reardon]

First I have to say how pleased I am to see so many creekers that are also fish keepers like myself. I built my first stand for a 75 gallon tank using 2 x 4's, 1/2" plywood and a few billion screws! Not a drop of glue and I was in such a hurry I never even put a finish on it. At the time I had to borrow the tools; what I found was a couple of phillips head screwdrivers, an ancient somewhat dull handsaw, a brace, a few bits, and a torpedo level. Of course I was also 15 and really eager to have a large tank setup in my room! Ignorance is bliss eh!

My point Ryan is that for this project simpler is better. As others have stated the weight, (unless this is an acrylic tank) rests on the bottom rim of the tank, and most of that weight falls on the two ends. This is where the support is needed.

I have since built 4, (maybe more now that I think about it) additional stands with all the bells and whistles, (canopies, drawers etc) for friends of mine and they do look nice. However, I still stick with the basics, add ons are just that.

Also mentioned above but easily overlooked in the excitement of setting up a new tank is to level the stand before you begin filling up the tank. I once helped a guy with a new 180 tall and in our haste we forgot that little item. To this day he has about a one inch drop from side to side.

One last note Ryan, a simple addition I always include in my new stands is a spot inside the cabinent where I attach a power strip. I put a couple of access holes in the back to thread cords through. There is just nothing worse than crawling around on the floor reaching behind the stand to plug or unplug an accessory. Plus all your cords should have a little drip loop below the power strip just in case any water manages to get on the cord during weekly maitenance and this way I can visually check that the loop is there. Water flowing down a cord into a receptacle is really bad juju!

[Ryan Sparreboom]

Thanks for all the responses and help guys. I'm also glad to see so many people on here are fish keepers too! I've had aquariums for years and am very aware of the need to level the stands and how the weight is distributed on a glass tank.
It is a glass tank and will be in the basement of his house, so just sitting on carpet and underlay over a concrete basement floor.

Our real endeavor hear is to build a stand that IS NOT a typical square cabinet design. That would be easy, but not what he wants it to look like.
I am still planning to go with the octoganal pillars. As I stated they will be directly under the corners as well as supported in the middle by an octaganal cabinet.

Here is a google sketchup I did. It's pretty crude but hopefully you get the idea.
My main concern is that if the top and bottom pieces are 1 1/2" thick (double 3/4" Birch Plywood) is it supported well enough with the spaces between the pillars?

Phil's Stand.skp

Thanks

*ignore the cutout pieces in the top, the top will be solid.

[Tim Byars]

Another opinion from a reef tank owner here...

While I suspect your design will work, I would be slightly nervous about that relatively unsupported front edge. But then, I've only built one for myself (for a 180 gallon tank), and it is quite a spectacle of paranoid overbuilding.

My suggestion is to run the idea past the folks at some of the big reefer forums (they tend to have some of the biggest setups), someplace like reefcentral.com or reefs.org. The mix of the woodworking knowledge here and the abundant experience there (with both successes and failures galore, I'm betting) might make the picture clearer.

[Josiah Bartlett]

Given the tank size and rather large cantilever of a front lip, I would build (or have built) the structural part of the frame out of welded box section steel and wrap it with wood.

I merely have a 55 gallon aquarium, and I also built my stand, but really just like a beefed up rail and stile sideboard with internal bracing.

One thing that most people forget about with aquariums is that they are very top-heavy. The stand is going to be subject to racking load in case of someone running into it or an earthquake. Any stand needs to be quite well crossbraced or you are asking for trouble.