[agro]

Built this stand out of 2x4s, bout 4' Long and 2' Wide.

Basic build but due to imperfections, of wood and my brain, the bottom left leg is not straight at all. So a gap forms when fitted in place and attempting to glue/drill to top frame. It's imperfect but it should hold.

My plan was to place a 20long fish tank so i'd say a good ~200lbs of weight would be on that. This is how the bottom left corner is, if the other 3 corners are fitted well would the tank be fine placed in opposite corner? (Top Right) This would be with some form of plywood of course.

 

[agro]

Is the 4th leg level with the other 3, at least? If so, you could just add a shim where the gap is located. If not, can you disassemble that leg and rebuild it, or is it stuck where it is because of how everything else was built around it?

Was built in a closet. So disassembly would take some time.

I have shims I bought because I know the floor is not leveled, wasn't sure if I can use it to fill gap, would have to glue and drill screw through.

 

[agro]

Any way of pulling it together with a clamp and screwing it tight?

Took the top frame out and opened the corner to somewhat work around the twisted leg.

Can't do it with a clamp cause I'd like a good tight bar clamp.

Bought multiple brackets and more lumber to support the upper half lot better. Will post a mock up or something when I can.

 

[agro]

I might be concerned if you were building for a 200 gal tank, but 2x4's are WAY overkill for 20g. As long as the aquarium is level that stand will support it no problem.

Bottom frame will support 4x10g, top will have 20g solo with some objects here and there.
Which i doubt really affects anything. Either way went ahead and bought more support. Some braces and a bit more lumber shall do the trick.