Steve B wrote:
I need a vacuum that I can put into a pipe, and have it suck out the
contents like a vacuum. Not a sump pump that is lowered, or a pump
that needs to be primed, or even a self priming pump. I need to
occasionally pump a four inch vertical pipe where fluids accumulate
below grade, and run it out 200' downhill through a 3/4" hose. Doing
that will create some suction and head pressure on its own. Almost
all pumps are larger than 4", and those that have a garden hose
intake are flimsy and the impeller won't take much solids and sand,
which may compose some of the content.
Ideas?

I thought of getting a dedicated wet vac, and putting a through the
hull fitting on it that would drain the water out of the tank,
putting a 90 ball valve on there, and opening it when the tank got
close to full.

Get a fire hose. I see 'em on Ebay from time to time. A 2" canvas hose won't
cost much.