I think you should add some more 2X4s around the legs, that way the 2X4s going horizontally across the top have more support.
Better safe than sorry with a monster tank like that.
Also, if you want you can close the sides with plywood, that really strengthens against tipping over. The 4X4s will do the job holding it up, but its useless if it'll tip over from leaning on it.
Better safe than sorry with a monster tank like that.
Also, if you want you can close the sides with plywood, that really strengthens against tipping over. The 4X4s will do the job holding it up, but its useless if it'll tip over from leaning on it.

