Calling all woodworkers: questions about framing to support 300lb fish tank

Using 2 x 4’s the walls will be thicker… from what I have seen in other builds correct?

What I was trying to do was stack the two by twos on top of eachother between the 2 plywood sheets essentially making a solid wall

I’m going to suggest that if you do not understand that a 2x2 and a 2x4 have the same nominal thickness then you probably do not have the carpentry skills to build a stand that will support an 8ft long tank that will weigh 3/4 of a ton.

I do understand the nominal thickness… but if you look at most wood aquarium builds the person put the two by fours vertically spaced apart 8 - 12 inches. Which leaves a lot of space in between the 2 x 4’s obviously.

I was wondering if it’s possible to literally make a solid " wall" by stacking the 2 x 2’s so that there is no space… anyway I will figure it out

If I had this tossed to me as a project, my first thought would be to construct a set of shelves. I’d use 3/8" or 1/2" plywood and 2"x2"s. Solid panels at the back and sides with internal 2"x2" posts at the corners. 2"x2" “joists” across the top front to back and plywood on top. Two internal plywood shelves would keep it in shape without additional cross bracing. One or two posts at the (open front). It would be plenty strong enough and you have a nice space for books, fish supplies, whips and chains, etc.