Thanks so much for the comments. The flow in the tank will 4 sources and 2 actuated ball valves. It just happens all intakes are in one end.
This will take a while to get finished. Lots of work ahead.
You might not believe it, but the first thing I thought when I saw it pull up was: I should ahve gone 12'x5'x30" instead of the 10'x4'x30" I went with. However, this is and will more than plenty. I know nothing is permanent in life, so I am building this with the far and remote idea that I may ahve to move it at some point in the future. If I do, 10' long will fit in just about any house while 12' would be a challenge to say the least.