Or instead of the cinder block (rocket engineer for current stand OR cinder with slightly larger tank)

[Daphne's_Reef]

I still haven't made the cinder block stand for my tank. I've currently got a 20 long I'd like to eventually try to make into a sump again, so I keep looking at it like "but I wouldn't be able to fit it under the blocks. . .

Option A: Rocket Engineer's 2x4 stand. The big issue I've got with that (besides being terrified I wouldn't be able to get it 100% square) is I don't want to skin it, I'd rather have it open if I did it that way, but I've seen tons of things saying you have to skin it or it'll sheer sideways and end up with your tank on the floor in pieces. Is that a huge issue for a 40 breeder, and without skinning with plywood, is there a different way to make sure the side to side is not going to be an issue on a 3 foot tank?

Option B: Get a 60 (breeder?) since they're on sale at petco now, and do a DIY AIO conversion for it. I'd need to find more egg crate for the lid, and need to find a hangar for my lights (I used to have one? Not that I know HOW to hang them) and they might not be long enough (24") for the nearly 4 foot span of the tank. But my fish would be happier, and I could maybe get another one or two for it at some point, and putting a few stacks of blocks under it, I'd still have plenty of room for the jug for my topoff.

I'd honestly prefer to stick with the 3 foot tank, but I would be willing to do either. Which seems like a safer bet?

Sorry I'm so indecisive and have too many questions!

 

[mfinn]

Unless you can do complicated Japanese joinery, using plywood on a 2x4 frame is part of the deal.
With the weight of an a 40 gallon aquarium 3' off the floor and just 2x4's for a stand it is very top heavy and subject to shear, front and back and side to side.
If you are into a industrial look with thick diameter lag bolts and galvanized brackets it could be done, and adhesive.
I did it once a long time ago and it lasted about a year before I noticed a real wobble when I bumped it.

 

[Cichlid Dad]

Build Your Own Aquarium Stand

Every Aquarium Needs a Stand and Sometimes It's Difficult or Expensive to Find a Stand That Suits You. Sometimes You Find Something You Like, but You Aren't Sure It Will…

cflas.org

Here are some examples for an open design. Showing both block and 2x one is a 4ft 90 other is a 55 gallon

 

[blecki]

You need to deal with shear but that doesn't necessarily mean skinning it. Skinning it is just so incredibly effective at it that it's usually the best choice. At 40-breeder size the doubled 2x4 legs shouldn't have much shear. Neither of my 75s are skinned and neither wobbles - in one, the corner legs are 3 2x4s each; in the other, I added a diagonal brace on each end. Squaring it up is easy but you need to build it tight.

IMO that cinderblock example looks awful. And has way less space underneath.

And it's not aligned the way cinderblocks are meant to bear load.

 

[twentyleagues]

I dont have my phone with me right now or id take a pic of all the tanks in my fish room. 80% are 2x4 stands that I built wide open not enclosed. I do use plywood for under the tank so that adds a little structural integrity. Also I suck at building stuff its never perfect but no issues most of these have been up for 4+ years.

 

[exnisstech]

My 40g breeder on 1x3" wood stand. Rocket engineer said it is beyond sketchy but it's been beyond sketchy for over 2 years lol Some of the stands I see people build could support a house.
EDIT : for obvious reasons this is not a recommendation for stand construction. Follow my design only if you have a high risk tolerance

 

[exnisstech]

And it's not aligned the way cinderblocks are meant to bear load.

Nice catch. I missed that and I used to labor for block masons.

 

[The_Paradox]

Had one of my stands open architecture for years before closing it in. Was 2x4 faced in 3/4” maple. I closed in sides with magnetically fastened panels and the front I just made standard shaker doors.

 

[twentyleagues]

Had one of my stands open architecture for years before closing it in. Was 2x4 faced in 3/4” maple. I closed in sides with magnetically fastened panels and the front I just made standard shaker doors.

Nice! I had planned to do that with one of mine just havent gotten around to it. Now with a 75g sump under a 28x28 tank I wont be able to lol.

 

[Cichlid Dad]

You need to deal with shear but that doesn't necessarily mean skinning it. Skinning it is just so incredibly effective at it that it's usually the best choice. At 40-breeder size the doubled 2x4 legs shouldn't have much shear. Neither of my 75s are skinned and neither wobbles - in one, the corner legs are 3 2x4s each; in the other, I added a diagonal brace on each end. Squaring it up is easy but you need to build it tight.

IMO that cinderblock example looks awful. And has way less space underneath.

And it's not aligned the way cinderblocks are meant to bear load.

First off does that look like a display tank? It is a holding tank, used in a emergency, second we are talking about 600 pounds. Not a building. Alignment in that way has a level perfectly flat surface for the tank. Put the other way is unbalanced do to an imperfect surface.

 

[Cichlid Dad]

Nice catch. I missed that and I used to labor for block masons.

Really? After you show your example?

 

[exnisstech]

Really? After you show your example?

I didn't mean that it was unsafe. I just meant the blocks are laying on their side instead of how they are meant to be used. My stand is definately not over engineered.

 

[Kodski]

So many people misunderstand statics that it makes it complicated to know what is right and wrong due to the misinformation many spread..

Can you build a 2x4 stand and not skin it. Yes you can. I've done it several times. Including my most recent build.

So I'll try to give you some advice tailored directly for you. Firstly though, let me say this, most stands you see are completely and irrationally overbuilt. I believe this is mostly due to lack of understanding statics, and partially because overbuilding something is a lot safer than riding the fine line of just enough. I believe however, that figuring for just enough plus a safety factor is all you need. We need X, so figure X plus a safety factor of Y is basically how everything in our world is built, including our aquariums.

Shear force like many have mentioned is the main reason many people consider sheathing the outside of stand necessary. There are many other ways though. I personally find that gluing all joints is a great way to strengthen a stand and keep it from racking. Gusseting is the next best and sure fire way to make sure your stand doesn't rack. There are a few ways you can do this. Using extra wood at diagonals is one way like exnisstech did in his 1x3 stand. I would recommend one on each side and one on the back. You don't need one in the front if you are using 2x4's. Another way would be to use metal brackets/braces. Your local hardware store will carry something to suit for sure. Some people may say that these arn't enough, but I can assure you that they will be.
Here is one example of a bracket you could use.

Simpson Strong-Tie 3 in. x 3 in. x 1-1/2 in. Galvanized Angle A33 - The Home Depot

Not only do angles make joints stronger, they also provide more consistent, straight corners. Simpson Strong-Tie offers a wide variety of angles in various sizes and thicknesses to handle light-duty jobs

www.homedepot.com

And here is the load chart for this type of bracket

C-C-2024_p302.pdf

ssttoolbox.widen.net

If you were to use one of these on each corner on where the top of your stand connects to the legs, you would have a minimum shear rating of 2,210 lbs in any direction without factoring in the addition sear load from the joinery and screws. From 8 brackets which would cost less than a sheet of furniture grade plywood. You could put the brackets on the bottom but really, with a rocket engineer stand, the load is transmitted through the legs into the floor, so there really isn't any benefit to doing so.


Another option all together would be to build a plywood stand. Much, much stronger overall while being much slimmer and minimalistic. Here is one I built. Since everything is glued. screwed, and half lap joinery, again there is no need for additional diagonal bracing. This is an 80 gallon tank, and since its so shallow the stand itself is built much higher than typical which means that sear force is generally greater than most applicaitons.

 

[BeanAnimal]

Unless you can do complicated Japanese joinery, using plywood on a 2x4 frame is part of the deal.
With the weight of an a 40 gallon aquarium 3' off the floor and just 2x4's for a stand it is very top heavy and subject to shear, front and back and side to side.
If you are into a industrial look with thick diameter lag bolts and galvanized brackets it could be done, and adhesive.
I did it once a long time ago and it lasted about a year before I noticed a real wobble when I bumped it.

Meh - I cobbled together a 2x4 stand for a 55 decades ago and it withstood house party type abuse...

I don't disagree that the shear panels increase strength by magnitudes, but you can pretty easily design around the need for modest sized tanks.

Edit: @Kodski replied while I was typing....
I wrote a deflection and calculator (don't think I finished the output format of the calc... lol)

Beam Calculator – Second Moment and Deflection | BeanAnimal's Reef

beananimal.com

and never got around to writing the twisting and buckling article or calculator... One day maybe...

I think the question here is what size tank is the OP looking to get?

 

[Reefering1]

40g ;-)

 

[Kodski]

Meh - I cobbled together a 2x4 stand for a 55 decades ago and it withstood house party type abuse...

I don't disagree that the shear panels increase strength by magnitudes, but you can pretty easily design around the need for modest sized tanks.

Edit: @Kodski replied while I was typing....
I wrote a deflection and calculator (don't think I finished the output format of the calc... lol)

Beam Calculator – Second Moment and Deflection | BeanAnimal's Reef

beananimal.com

and never got around to writing the twisting and buckling article or calculator... One day maybe...

I think the question here is what size tank is the OP looking to get?

I also tend to disagree with most people on the fact that for most applications adding additional shear strength isn't necessary. In reality, using the correct fastener has a bigger effect. Most screws are not designed for shear strength, but even so, the weights we typically see paired with the amount of screws typically used in this application generally won't ever create any issues. Such as your experience. Here is a shear load chart for a typical GRK deck screw.

Most people use #6 or #8. But even still at #4 sizing, if we figure a person uses 4 screws per corner, that's 556lbs of shear strength per corner. So a finished stand would have 2,224lbs of shear strength. Hence why I don't believe sheathing most stands is necessary.

 

[BeanAnimal]

I also tend to disagree with most people on the fact that for most applications adding additional shear strength isn't necessary. In reality, using the correct fastener has a bigger effect. Most screws are not designed for shear strength, but even so, the weights we typically see paired with the amount of screws typically used in this application generally won't ever create any issues. Such as your experience. Here is a shear load chart for a typical GRK deck screw.

Most people use #6 or #8. But even still at #4 sizing, if we figure a person uses 4 screws per corner, that's 556lbs of shear strength per corner. So a finished stand would have 2,224lbs of shear strength. Hence why I don't believe sheathing most stands is necessary.

I typically use through bolts and washers where the fastener shear strength far exceeds the tear-out or splitting strength of the wood itself. Even here, people tend to overkill - 5/8 bolts on the legs for a 120 when 1/4 or 3/16 would provide more than enough safety.

 

[Daphne's_Reef]

It's a 40 breeder. I've already got that tank

Holy cow, SO much advice! I don't have the tools I'd need to cut sections out of the plywood sheets (and the cost would skyrocket, I'd think? More than buying a commercially built stand anyway, just in the wood and sealant) so that's likely a no-go. Honestly, I have a drill and that's about it, so I was hoping to get the store to cut the boards and just make sure they were all accurate before leaving.

So it seems the safest bet is still to go for the cinder blocks in an L shape at the back/along the sides and have 2x4 or 2x6 boards across the top for the top of the stand to rest on, then? I definitely cannot afford to have my tank hit the floor.

Though since that would stick out by about 6" on either side (and I'm a bit of a klutz and WILL trip on a 2 foot tall tank stand at some point) is there a way to get them to not extend past the edge of the tank? Putting them horizontal to each other, perhaps, or using the 8x8x16 for the back side, then 8" cube ones for the front corners so I could still at least fit the topoff jug under it? Or is that too risky as well?

 

[Kodski]

It's a 40 breeder. I've already got that tank

Holy cow, SO much advice! I don't have the tools I'd need to cut sections out of the plywood sheets (and the cost would skyrocket, I'd think? More than buying a commercially built stand anyway, just in the wood and sealant) so that's likely a no-go. Honestly, I have a drill and that's about it, so I was hoping to get the store to cut the boards and just make sure they were all accurate before leaving.

So it seems the safest bet is still to go for the cinder blocks in an L shape at the back/along the sides and have 2x4 or 2x6 boards across the top for the top of the stand to rest on, then? I definitely cannot afford to have my tank hit the floor.

Though since that would stick out by about 6" on either side (and I'm a bit of a klutz and WILL trip on a 2 foot tall tank stand at some point) is there a way to get them to not extend past the edge of the tank? Putting them horizontal to each other, perhaps, or using the 8x8x16 for the back side, then 8" cube ones for the front corners so I could still at least fit the topoff jug under it? Or is that too risky as well?

I would still go with a 2x4 stand. If you can get the store to cut all the boards all you need is a drill. Which you mentioned is all you've got. While they are cutting the boards, just pick up some of those L-brackets I mentioned and some decent quality screws and you'll be fine! In the end, you'll appreciate the extra bit of work. Personally, I feel cinder block stands are much less strong than a wooden stand when you take into account the inconsistency of concrete.

You mentioned earlier than you were scared you couldn't get it square. To be completely honest, square is nice, but not needed! Having a flat stand is much more important and you can achieve that by just feel. Plus, since you're going with a 40 breeder, having a rim makes it more forgiving on that front at well. Flat is more important because in reality, you'll be shimming the stand anyways. So if its a little out of square, its really not a big deal. Besides, you can make a stand as square as possible and you'd still have to shim due to the floor itself. So focus on making sure you don't have one board protruding further than the other and you'll be just fine!

 

[Daphne's_Reef]

How do I shim it? Under the corners of the stand itself? Do I tell if it's flat by just putting the tank on top of it dry and seeing if there are any raised spots? Does that just assume it won't be square and flat when it's built/placed?

Where do the L brackets go? Under the top railing on the 2" sides of the 2x4s?

What screws should I use? I'd be grabbing them from Lowe's, but there are a million and a half packages there. Self-tapping would be great so I don't need to pre-drill. Other than that, I'm open to suggestions.

Just need something good for the tank is all! To be honest, if anyone had an idea for a way to make water changes not a nightmare, I'd be quite content just setting the thing on the floor instead and calling it good.