I got the basic stand frame done today. I still want to put two joists with hangers in the middle, but LVL's need special hangers and nails. I would like to find someone in Calgary that stocks them. Home Depot wants 10 - 14 days to order them in.
I used 1-3/4 X 9-1/2 LVL for the beams (doubled up front and back) and 6 x 6 treated dimensional lumber for the legs. I'll be moving the tank into place using an engine hoist, so I needed clear floor under the stand to allow for the hoist wheels. With the strength of the beams, I won't need any other support underneath, but I may still frame up a wall under the back and sides then sheet it with plywood to prevent racking of the stand once the tank is loaded with water and rocks.
Alternatively, I could put in some knee braces to give it a timberframe look.
I like using engineered lumber for stands because it's simple, beefy and straight.
I used this laser level to level things:
