The stuff I have good info on is this:
Advance X-1 Bio elements The price jumped from ~ $37.00 to ~ $52.00 per cubic foot. Shipping is always higher than you want it to be. For some reason, they have to use a super sack and ship freight. They also charge ~$49.00 for the super sack.
I only wanted 8 cu-ft, which I don't need that much, but emailed them to see where price breaks are on quantity. That could be the reason for the price jump, because previous quote was for 14 cu-ft.
I think you should look at what the active surface area is rather than the total surface area.
