Transferring water from one sump to another
A manual suction pipe (or perhaps a commerial siphon?) will transfer fluid until the fluid level is equivalent (or level). A commercial siphon will operate for a perhaps a couple of hours; a simple pipe or a hose will operate for a 20 or 30 minutes perhaps. But siphons will eventually fail as fluid evaporates and bubbles eventually fill in the siphon's reservoir. 

How long the siphon will continue to operate depends on the rate of bubble formation, which depends mostly on the height of the hose (gravity will cause a vacuum at the top) and temperature (cold water will allow a siphon to operate longer than steaming hot water).