Son called, dad I need help

[jackde]

My son bought himself a new Diablo skimmer for christmas. Only problem is skimmer is 6" in dia. and he only has 5" between sump and stand. Well since it does look nice sitting on the floor it would look better in the sump. Now it's dad can you build me a nice new stand with more room inside?

Thought I would share this build as it goes along. Guess I should mention that stand is for a 75 gal. reef.

To start I built a basic frame with 2x4 legs. Used scrape plywood and trimed legs at 45's.

Here I added some ply to the corners to level top with the bottom.

Next I added solid cherry face frame to the 4 sides.

Then fooring was installed for tank and sump.

Now he is going to have to wait for me to start on trim, doors and a canopy. Wife says no more saw dust till after the Holidays.

 

[fishgate]

ohhh..... I really hate to say it the stand looks very nice, you should rebuild that stand. Even though you added the sides to it, you are using the screws to hold the entire weight of the tank. Not a good idea. The tank frame should be supported by wood all the way to the floor.

 

[jackde]

Ignore the face frame, inner frame that supports the tank is wood to the floor. Corner posts and ply are glued along with the screws.

 

[fishgate]

Yes, I am looking at the inner frame. It is not proper construction for a fish tank. The outer skin actually helps strengthen it but would still not allow me to sleep at night. Search the DIY forum for similar threads. I wish you had come here first.

 

[fishgate]

Also I think you need at least 1 support front and back in the center for a 75g tank. We are talking around 800lbs. It will sag in the middle causing a possible tank rupture. I have a 40B tank and without the center support I am certain the tank would fail.

 

[e43devil]

Looks great! Might want to add a little more shear safety, but looks fine to me. Unless you want to add a steel I-beam and some 8x8's!!!!lol

 

[sleepydoc]

How did you join the face frame? Did you use pocket screws for that as well?

Looking at the way you have it designed, the weight will be transmitted on both the triangular pillars as well as the plywood frame outside of it with the plywood top helping to distribute the weight?

You can get by without a center support for a 75 gal (4 foot) tank - I've seen stands for 120s that don't have them, but they have to be designed properly. The cross beam looks to be 3/4" ply, so essentially a 1x3 microlam beam? Is the plywood top anchored/fastened to the underlying structure, or just resting on top? If it is attached it will add some strength as well, but my gut says it would probably need more support. I have nothing to base that on, though, just a gut feeling. A plywood beam on edge is pretty strong, so it might do.

Many of the stands I've seen are significantly over-constructed, and while it doesn't hurt the structure, it isn't necessary, either. The generic Marineland stand I have for my tank is made out of 3/4" particle board. No solid wood vertical supports anywhere. It does have a center support, though.

I have looked and haven't found any data for deflection of a plywood beam on edge, or for allowable deflection of an aquarium, so it's really hard to say whether any design would be adequate.

 

[sleepydoc]

double post

 

[jackde]

Face frame is put together with pocket hole screws and glue. It is attached to inner frame approx. every 6" with screws. The 3/4" flooring will be atttached after finishing but only to prevent any movement in the stand. Tank rests on plastic trim, bottom glass does not touch. From what I've seen of store bought stands this thing should hold two tanks stacked.

 

[fishgate]

On store bought stands and most stands built here by members, all of the tank weight is transferred to the floor via wood. On your build, if you removed the screws, your stand could possibly fail. That is the main (and critical) difference. Your saving grace is the board that you put on the top to support the tank. However, the main support for that board is the ends of the 4 upright 2x4s, not the screws that hold the tank frame to the 4 upright 2x4s. This means that the tank is supported by the board, but in reality, the frame of the tank does not have the typical recommended support from the frame to the floor. Will it be ok? Probably. But again, we are talking about close to 1000lbs of weight.

I also still think you need a center support. At least measure the distance between where the support should go and the bottom of the stand and then measure again after the tank is full to see how much bowing you get. I am guess it will be at least 1/4". That puts a lot of stress on the glass.

 

[uncleof6]

The top frame, that supports the tank, is in shear with the vertical supports. This is improper construction, as has already been pointed out. There may not be much to manufactured stands sitting at an LFS, but the one thing they do have is support in compression from the bottom of the tank to the floor, which has also been brought up. Compression means the verticals hold up the top frame--top frame sits on top of the vertical--rather than having nothing but screws holding up the tank--which is not wood from the bottom of the tank to the floor. The top rim in shear is unsafe, and unsound. Personally, I would not put a tank full of water on it.

 

[bmiller1234]

Fishgate. Your looking at the wedge cut 2x4's which are just a nailer for the actual supports that are ply between bottom and top frames. It's not ideal but will support the weight. The actual "proper" plywood stand would have each side cut from solid sheet but this design is more than sufficient.

Jack nice looking stand.

 

[bmiller1234]

Uncle and fish. Look at pic 3. They are corner supports to floor.

 

[uncleof6]

Uncle and fish. Look at pic 3. They are corner supports to floor.

Those are the verticals I am referring to. However, what holds the tank up, is attached to those verticals using screws in shear: the top rim. The verticals are not supporting anything, the screws are. That is the problem. Stand is unsound, the top rim needs to sit on top of the verticals.

If the cherry face frame was attached directly to the verticals, rather than the way it is now, (top rim in shear) the stand would be way stronger, and would support the load.

 

[fishgate]

hmm... ok I think after really studying pic 3, it does look like there is another board added between the top frame and bottom frame, in which case I withdraw most of my complaints! However, I still think you need a center support for this size tank.

 

[pjhaddock]

With it being a 4' tank, as long as the supports on the corners are solid from the bottom of the tank to the floor it will be fine. Looks great! I put a center support on mine where the 2 doors will meet that is tight, but comes out if I need to remove the sump or something like that. In this pic you can see where it goes. It fits so tight that I don't have to secure it in any way.

 

[bmiller1234]

Those are the verticals I am referring to. However, what holds the tank up, is attached to those verticals using screws in shear: the top rim. The verticals are not supporting anything, the screws are. That is the problem. Stand is unsound, the top rim needs to sit on top of the verticals.

Are you seeing different pics? Pics 1-2 show a floating top ply frame and bottom ply frame that tank would sit on. Pic 3 shows the space filled with ply veryical supports. It's basically a rocket design using ply instead of 2x4. The vertical 2x4 wedge cut is just a attachment point.

 

[hllywd]

Pic #4 shows the compression pieces between the top, and bottom rims. It's right behind the 12 in the date. As for a center brace, most commercial stands have them. On several occasions, I had the front, center brace of my AGA 120 stand out to move equipment. Using a tape measure, there was no detectable deflection with one center support removed. The AGA stand was solid 1X pine of similar construction to the OP's. While I might add removable center supports, I think this stand will work fine.

 

[RocketEngineer]

Folks, take a look at this picture:

Here I added some ply to the corners to level top with the bottom.

First, the picture is turned on its side. That puts the boards under the tank on the left hand side and the boards on the floor to the right. FYI, I had to look at it 3 times before I wrapped my head around it.

Second, there is a pair of plywood pieces on either side of the corner going from under the top frame to the bottom frame. The cherry face frame isn't load bearing from what I can tell.

I think you will be fine. The corner support will ensure that the plywood does its job properly. Being a 75g and having 8 vertical pieces really spreads the load around.

Keep us posted.
RocketEngineer

 

[TucanSam007]

How did you join the face frame? Did you use pocket screws for that as well?

Looking at the way you have it designed, the weight will be transmitted on both the triangular pillars as well as the plywood frame outside of it with the plywood top helping to distribute the weight?

You can get by without a center support for a 75 gal (4 foot) tank - I've seen stands for 120s that don't have them, but they have to be designed properly. The cross beam looks to be 3/4" ply, so essentially a 1x3 microlam beam? Is the plywood top anchored/fastened to the underlying structure, or just resting on top? If it is attached it will add some strength as well, but my gut says it would probably need more support. I have nothing to base that on, though, just a gut feeling. A plywood beam on edge is pretty strong, so it might do.

Many of the stands I've seen are significantly over-constructed, and while it doesn't hurt the structure, it isn't necessary, either. The generic Marineland stand I have for my tank is made out of 3/4" particle board. No solid wood vertical supports anywhere. It does have a center support, though.

I have looked and haven't found any data for deflection of a plywood beam on edge, or for allowable deflection of an aquarium, so it's really hard to say whether any design would be adequate.

My 65 g marineland stand has no center support. I actually used the backside as the front (for wider opening) and put in vertical supports on the corners (1x3). Couldn't trust it lol...although it's been a year now and still going strong with the mods