I'm going to be creating a small concrete slab (30" x 30") used to hold a 120 gallon propane tank. I have a few questions:Do I need rebar?Should I lay down gravel as a base prior to pouring the concrete?Can I use 2 x 4 wood for the forms?EDIT: 2x4, not 4x4 via /r/DIY http://bit.ly/2N5yLSE
