Ok, I drew it up again from scratch
... I currently am not able to work on it and have quite a bit of free time, so I can keep drawing it up as many times as possible.
I replaced the 4x4's with 2x4's, and I think the way I designed it, it should pre pretty rock solid. I didnt know how to draw diagonal 2x4's in sketchup, so I went with plywood. I also raised the MLT up high enough to put the march pump underneath it, however it should prime just fine in the old position because the water level would have been above the pump inlet, right?
It seemed like it would be more stable if the pedestal supports had a collar around them and the flat of the pedestal on top of that. If that isn't true, and I will need more support/stability I will rework it, although it seems like it will be very stable, especially if you look at the image of the bottom.
Is there anything wrong with using large framing screws to put this together? I have a nice drill, but no nail gun ... so screws seem like the easiest assembly solution.
Here is version 2.0:
And here it is with no vessels: