best method of raising up metal stand to 36"

[monocus]

use 6x6 posts covered with plywood.you could put a doorskin cut to hide the posts.you can also leave a space for your drain and returns

[The Grizz]

Now this is only my personal opinion and not saying how the stand is built but the use of 2" is not required. Again only guessing that the tubing is a lite wall tube, maybe 120 wall or thinner. I only use 1 1/2" 125 wall tube for each and every stand I have ever built including the one that is under my 300 gal 8'er. If built correctly with the front & back frames mitered at a 45* to make the corners & the joining tubes over the miters it will never budge an inch.

With your stand I would make a frame 6" tall out of 1 1/2" tube to sit on top of your stand, this might allow more room for your bulkheads. The 2 frames could be bolted together with stainless steel bolts so they do not shift.