Those would be the plans seen, Freshy. :nutkick: I know it because I gave the link, initially. :raspberry:
You have a few options. If your cinder blocks (I've never looked at available sizes) aren't 18 inches or so, find out what size they are, and maybe do multiple columns. You could have one "leg" of the stand be cinder blocks in an H shape or = shape. I'd recommend keeping each "leg" as symmetrical as possible, so no T shapes, just to create more stability. You just want to have it stable.
So, it looks like they're typically 16 x 8 x 8, according to wiki
http://en.wikipedia.org/wiki/Concrete_masonry_unit. A typical (assuming you have a standard) 75 has a perimeter of about 48 x 18. I would lay the holes vertically, and I would have the blocks about 2 inches apart across the 18 inch side, and as high as you want them. Basically, looking top down, you're going to have an = sign that runs the length of both sides of the tank, and you should be able to see floor through the holes in the blocks. So, at a guess, you're looking at 3 (length) x 2 (for each long side) x 3, or 18 CMUs, if you want the stand in the neighborhood of 24 inches tall, excluding painting, and wood. The layer of plywood should distribute the weight, so the 2 inches or so down the center of the length of the tank won't be noticeably unsupported.