The filter tank is only going to hold 25gallons of water, that is without the media, the media, I have chosen is also quite light, K1 in the first compartment, pop soil in the second and third compartment, and will be growing some plants along with them.
The base of the filter tank is 0.5" thick and I have been running these kinda filters on 6 footers too, and the base holds.
There's a lot more to be done, although this weekend I did finish adding the background, added the inlet plumbing for the filter.