Stand or not for huge plywood tank

[SeabeeShrek]

I’m currently designing a plywood tank roughly around 1900 gallons. I like the idea of no stand, but then I have to build an area for my filtration. I’m interested in your input here. The area it’s going in has cathedral ceilings , so height isn’t the issue. It’s just the extra weight is a concern. Also being in SWFL, it’s on a concrete slap with 24” tiles.
The pics show the direction that I’m going, except that the window will be 72 x 44 3/4”
If I keep on the floor it’ll be 4x4 base with 2x6 framing.

 

[tlindsey]

I’m currently designing a plywood tank roughly around 1900 gallons. I like the idea of no stand, but then I have to build an area for my filtration. I’m interested in your input here. The area it’s going in has cathedral ceilings , so height isn’t the issue. It’s just the extra weight is a concern. Also being in SWFL, it’s on a concrete slap with 24” tiles.
The pics show the direction that I’m going, except that the window will be 72 x 44 3/4”
If I keep on the floor it’ll be 4x4 base with 2x6 framing.

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I personally would not worry about a stand and place filtration on the side or back of it.

 

[SeabeeShrek]

Thanks, unfortunately my mind doesn’t want to stick to one idea lol. No stand certainly is easier.

 

[aussieman57]

Also in SW FL and following to see how you build this.

 

[SeabeeShrek]

Top picture is the back wall. 10’ x 4’
Bottom is the front wall
6 x 6 post corners with 4 x 6 supports

 

[SeabeeShrek]

Top is the top cover with 2 view panels in front, 2 plant holes and the back holes are for access for cleaning.
Bottom is the sidewalls

 

[M1A1]

I would advise against any 4x or 6x material since it will warp, twist, and split far worse than you want. Instead you double or triple up on a more standard 2x, kiln-dried lumber which is also easier to handle and fabricate, and probably cheaper per board foot. Bonus points (strength) if you incorporate a layer of plywood into the laminate.

Otherwise, you are going to want more vertical bracing on all walls although usually a single 2x4 will suffice; think about 12-inch on centers or less. The risk of fewer supports is the plywood bowing outwards which puts more strain/stress on your fasteners/adhesives and ultimately your waterproofing. Even an 1/8" deflection can crack a coating and cause a leak.

 

[fishdance]

I went through a similar exercise on a 120cm deep tank and it's something only you can decide.
A tank at ground level is much easier to work with or on. You still have to climb in and out.
A tank with water level at or above head height is much nicer to look at.

If you do decide to use a stand, I would go steel and you might as well make the tank wall frame out of steel as well (All one unit).

 

[SeabeeShrek]

I would advise against any 4x or 6x material since it will warp, twist, and split far worse than you want. Instead you double or triple up on a more standard 2x, kiln-dried lumber which is also easier to handle and fabricate, and probably cheaper per board foot. Bonus points (strength) if you incorporate a layer of plywood into the laminate.

Otherwise, you are going to want more vertical bracing on all walls although usually a single 2x4 will suffice; think about 12-inch on centers or less. The risk of fewer supports is the plywood bowing outwards which puts more strain/stress on your fasteners/adhesives and ultimately your waterproofing. Even an 1/8" deflection can crack a coating and cause a leak.

I was thinking more vertical and horizontal framing on the back wall and one side wall. With the glass windows (oval side wall) I’ll have to get creative with the supports.
As for the 6x and 4x’s, I was thinking about the base frame, lag bolted with 2x’s rounding out the test of the build. I usually overbuild everything.

 

[SeabeeShrek]

Thanks for the advice M1A1