DIY Stand for Tank and Sump that are Same Width

[Hugh Mann]

I will preface this by saying evidently I am dumb.

Anyways, long story short, my old stand was ruined, and I have to build a new one for my 230 gallon.. The sump (with rim) is 24.5” wide. The tank is 25.5” wide with the rim.
The sump fit (barely) under the old stand, but now that I am looking at how to build stands (I did not build the original, it came with the tank), all the center supports stick out into the interior, and since the stands more or less match the dimensions of the tank, it means the sump won’t fit. Every design I look at calls for one 2x6 between the top and bottom frame and one behind it to hold it in place. (Pictured left, though I am sure you know what I am talking about)

Unless I am missing something, can the stand be wider than the tank? The original was, but not by very much. I will be using 2x6s for the frame and center supports and 4x4s for the corners. Topped with 3/4” plywood.

Pictured is the top down view of the supports to hopefully help illustrate the problem

Unfortunately I do not have the original stand, had to discard right away as “contaminated waste”, so I cannot refer to it, and for the life of me, cannot recall how the center supports were put together. Hence why I am dumb.

I should also mention my carpentry experience is barely above zero, this would be my first stand I actually built. Did I mention I am also dumb?

 

[455Cutlassdave]

Yes, the stand can be wider then the tank. If you set the tank all the way back you can actually make a nice shelf in front of the tank. I would wrap it with edge banding or trim to make it nice so that you cant see the ply. You are going to have to ensure good bonding of you cross supports under the plywood. I would recommend using screws and some titebond 3 at every connection point.

Also you are going to want to bond the plywood to the stand frame. This is so that if there is even the slightest deflection from the weight that it will not lift the plywood at the edge. I don't believe this would be a problem given how ridged 3/4 is.

 

[Hugh Mann]

Yes, the stand can be wider then the tank. If you set the tank all the way back you can actually make a nice shelf in front of the tank. I would wrap it with edge banding or trim to make it nice so that you cant see the ply. You are going to have to ensure good bonding of you cross supports under the plywood. I would recommend using screws and some titebond 3 at every connection point.

Also you are going to want to bond the plywood to the stand frame. This is so that if there is even the slightest deflection from the weight that it will not lift the plywood at the edge. I don't believe this would be a problem given how ridged 3/4 is.

By bond you mean like a wood glue? Noted.

I was planning on wrapping the stand itself with a nice finished plywood and staining it to make it look all purdy.

Taking another look at the plans, the tank would still sit over the 4x4s, just not the center supports. But seeing as the 4x4s alone can take 6x the weight of the full tank, they’re really just there to make sure the center doesn’t sag over time.

 

[455Cutlassdave]

If it were me having looked at your drawling again I would run an additional beam on the other side of each 4x4 and use a block sistered at each center support. Then run your cross members between those. That way the weight bearing beams would be under your tank and not at the edge. I will draw it up real quick and post it.

 

[455Cutlassdave]

Too bad your not closer. I built this one for a 72 x 36 before getting a great deal on an established 200g.

 

[adinin]

Going with the usual design, i would put the center supports directly underneath the beam that runs along the top. That way any force from the beam is pushing onto the top of the 2x4, and not resting on the screws. Maybe put a small piece of 2x4 or plywood to hold it there, but if you have a nice tight fit on the piece it shouldnt be going anywhere. You could even have a full piece of plywood along the front, and cut out in between the supports, or a piece that runs the height of the stand but just covers that support. That way its outside the internal dimensions of the stand. It all depends on how you want it to look, and what your willing to spend on materials. Either way, having that bracing for the support on the outside vs the inside shouldnt matter.

Not really a direct response to your question, but i would be cautious using 4x4s for the corner legs. I know when i was doing my research into building the rocket engineer design, people were talking about using 4x4s because they were stronger. The response of multiple people were not to use them, they had a much higher tendency to twist and warp in a high moisture environment. Plus the compression strength of a 2x4 is something like 18,000 pounds, and seeing as how there are 8 of them holding up the stand, its more then overbuilt just using them. Also, the supports on the inside are mostly to tie everything together, and (in his design at least) don't touch the top of the stand or the floor. You want all the weight transmitted down through the wood, not relying on the strength of the screws holding it together.

Anyway, dont want to scare you away from your plan, not even sure if you are following his design, just sharing what i came across. The original thread for his design is here, they are talking about the 4x4s and strength at the bottom of the first page.

 

[455Cutlassdave]

Great points. In fact in my picture above this is what I did with the wood under the beams. It was then sistered with another 2x4 to make a 4x4 size but without the tendency to twist and split.

This picture shows the step before the vertical supports were added. I glued and screwed them together and clamped everything while it dried. I probably overbuilt the stand but 300 gallons of saltwater staying where it is supposed to is worth the extra effort.

 

[Hugh Mann]

If it were me having looked at your drawling again I would run an additional beam on the other side of each 4x4 and use a block sistered at each center support. Then run your cross members between those. That way the weight bearing beams would be under your tank and not at the edge. I will draw it up real quick and post it.

I’m not entirely sure I am understanding how that center support fits in a way that allows room for the sump, or where the tank would sit in relation to the frame you drew. I assume the bottom of the frame would mirror the top?

My original design, if I did a poor job of explaining it was more or less like the other picture you posted, just 4x4s in the corners and the inner of the middle2x6s a little shorter as it is only holding the center support in place.

I reviewed what Adinin was saying about 4x4s, and a look at the stock of the local-ish Home Depot agrees that every single 4x4 is either split, bowed or twisted. Much better to just sister two 2x4s.

Speaking of which, the stand you showed be looks like you used 2x6s. I was also going to use 2x6s, but by the sounds of what they were saying 2x4s should hold the weight quite well with a good safety factor. Which is better to use, considering 2x6s are almost double the price. $6.18 vs $11 for 8 footers. I also already have a pile of 20 2x4s I was going to use for a different project but wouldn’t mind saving a buck using it for this stand if it’s plenty strong.

I also plan to wrap the frame in a finished plywood. Does the thickness matter for the sides at all? Would thicker add more strength or not matter?

 

[Hugh Mann]

Going with the usual design, i would put the center supports directly underneath the beam that runs along the top. That way any force from the beam is pushing onto the top of the 2x4, and not resting on the screws. Maybe put a small piece of 2x4 or plywood to hold it there, but if you have a nice tight fit on the piece it shouldnt be going anywhere. You could even have a full piece of plywood along the front, and cut out in between the supports, or a piece that runs the height of the stand but just covers that support. That way its outside the internal dimensions of the stand. It all depends on how you want it to look, and what your willing to spend on materials. Either way, having that bracing for the support on the outside vs the inside shouldnt matter.

Not really a direct response to your question, but i would be cautious using 4x4s for the corner legs. I know when i was doing my research into building the rocket engineer design, people were talking about using 4x4s because they were stronger. The response of multiple people were not to use them, they had a much higher tendency to twist and warp in a high moisture environment. Plus the compression strength of a 2x4 is something like 18,000 pounds, and seeing as how there are 8 of them holding up the stand, its more then overbuilt just using them. Also, the supports on the inside are mostly to tie everything together, and (in his design at least) don't touch the top of the stand or the floor. You want all the weight transmitted down through the wood, not relying on the strength of the screws holding it together.

Anyway, dont want to scare you away from your plan, not even sure if you are following his design, just sharing what i came across. The original thread for his design is here, they are talking about the 4x4s and strength at the bottom of the first page.

I think I did a poor job of explaining myself, but that is what my plan called for. The inner 2x4 would just be there for the actual support piece to get screwed into, holding it in place.

I have no idea why it didn’t occur to me to put that on the outside of the frame. Just that simple move should allow the sump to fit. Honestly, pretty sure that just jogged the ol’ brainbox and the original stand just didn’t have that piece and the support was just pressure fit like you said.

After reviewing 4x4s, and seeing what Home Depot had to offer, I absolutely agree, it is far, far better to sister 2x4s together.

 

[workhz]

Are you talking about putting the center support on the outside of the frame? Don’t think that would work as you want to load bearing down on the wood directly and not screws.

I’m sure there’s a million ways to do it with enough bracing. Even with screws etc when you look at shear specs.

I do wonder whether 2 doubled up 2x6 or 2x8 without a center support is sufficient. Curious what the deflection would be on that over 6’.

 

[Hugh Mann]

Are you talking about putting the center support on the outside of the frame? Don’t think that would work as you want to load bearing down on the wood directly and not screws.

I’m sure there’s a million ways to do it with enough bracing. Even with screws etc when you look at shear specs.

I do wonder whether 2 doubled up 2x6 or 2x8 without a center support is sufficient. Curious what the deflection would be on that over 6’.

No. The center support would be directly between the top and bottom frames. It’s just every design I look at calls for a second board behind it that it gets screwed into to hold the support in place and keep everything square.

Technically, a 2x4 in each corner would hold the weight of the tank while full. The link Adinin shared, an enginner type fellow stated a 24” 2x4 can hold 19,000lbs vertically if properly supported. Even what I read before that a 36” 2x4 would support 800-1000lb, 4 is still sufficient.

I have no idea how to calculate deflection, nor do I know what would be acceptable or not, but it is an interesting question.

 

[Weasel1960]

@Hugh Mann take a look at this thread, I am in a similar situation designing my cabinet. @RocketEngineer has a popular design in the DIY threads and responds to my questions. Maybe this may help you.

Good luck with your rebuild, glad you didn’t give up. Keep us posted with a new build thread.

edit forgot to post the link, here it is.

Modifications to RocketEngineers DIY Stand design

Looking for opinions on making modifications to what is referred to as Rocket Engineers DIY stand design. Would definitely appreciate @RocketEngineer chiming in. I am building next to an open stairway in limited space so want to put a vertical tower on the right side of the 4x2x2 tank. Will...

www.reef2reef.com

 

[RocketEngineer]

Ok! Who called for an “expert” ?

OP: if you don’t want center supports, make the top frame out of larger boards. A 72” spanned by a 2X8 would do just fine for that size tank, especially if glass. Make use the 3/4” plywood top is as flat as can be. Doubled up 2X4 uprights and a 2X4 bottom frame should finish it out. Adding cross supports top and bottom wouldn’t hurt and would support the sump ends.

HTH,
RockerEngineer

 

[workhz]

Ok! Who called for an “expert” ?

OP: if you don’t want center supports, make the top frame out of larger boards. A 72” spanned by a 2X8 would do just fine for that size tank, especially if glass. Make use the 3/4” plywood top is as flat as can be. Doubled up 2X4 uprights and a 2X4 bottom frame should finish it out. Adding cross supports top and bottom wouldn’t hurt and would support the sump ends.

HTH,
RockerEngineer

Not OP but I’ll ask so others have an answer. For the top frame do you place crowns up or down? I go crown down as it seems easier to shim but I guess could go either way of shimmed properly.

On house wall, it’s crown towards the outside. On a deck it’s crown up.

How about a tank?

 

[Hugh Mann]

Ok! Who called for an “expert” ?

OP: if you don’t want center supports, make the top frame out of larger boards. A 72” spanned by a 2X8 would do just fine for that size tank, especially if glass. Make use the 3/4” plywood top is as flat as can be. Doubled up 2X4 uprights and a 2X4 bottom frame should finish it out. Adding cross supports top and bottom wouldn’t hurt and would support the sump ends.

HTH,
RockerEngineer

It’s glass. 1/2 sides and 3/4 bottom, if that makes a difference.

How safe and secure would such a stand be, using 2x8s? Safety factors and all that good stuff. I understand that is some hefty wood, but not having center supports seems… sketchy, though it would make my life a lot easier. Especially if I ever had to remove/replace the sump. The stand height is going to be 36-40” tall, if that changes anything.

What would the frame look like, more like the design of yours that was linked, what I drew or what the other guy did, with the doubled boards?

Also, so I am understanding you. The top frame would be entirely 2x8s. The 4 legs would be sistered 2x4s for 8 total. Bottom frame also just 2x4s?

 

[RocketEngineer]

The red and yellow would be 2X8s. Everything else 2X4s.

I don’t work off a safety factor, I use beam deflection as my determining factor. In the case here, my goal is less than 1/8” deflection of the center beam span. For the design above, you have 65” unsupported. The lumber is 7.25” X 1.5”, and I split the ~2300 lbs load between the two for 1150 on each span. (This is simplified to make it easier, IRL, the span is taking less load.)

Working out the math, I get ~.086” deflection. To me, that’s acceptable. Ultimately, it’s up to you.

HTH

 

[Hugh Mann]

The red and yellow would be 2X8s. Everything else 2X4s.

I don’t work off a safety factor, I use beam deflection as my determining factor. In the case here, my goal is less than 1/8” deflection of the center beam span. For the design above, you have 65” unsupported. The lumber is 7.25” X 1.5”, and I split the ~2300 lbs load between the two for 1150 on each span. (This is simplified to make it easier, IRL, the span is taking less load.)

Working out the math, I get ~.086” deflection. To me, that’s acceptable. Ultimately, it’s up to you.

HTH

Looks good. Thank you very much for the advice. I have myself a fun project to do this weekend.

I suspect it will take longer to find enough people to lift the tank onto the stand than to build it.

 

[RocketEngineer]

HA! With COVID, my tank sat in the crate for 20 months. I hear you on that score.

 

[Hugh Mann]

Progress!

Two stands for a 20 high and 55 went quite smoothly. As did most of the 230 stand. Until this wee problem. Made all my cuts according to the design and measurements. Well, as it seems, the 2x8s were a little off in their width. Perfect flat and flush on the top, but about 1/8th off on a couple of the corners, resulting in the supports not actually supporting anything.

Gotta get some more wood to recut said supports. Dangit. It’s never easy.

 

[workhz]

Is it me or do you not have Ls for corners? As in what’s supporting the shorter side top pieces.