You might have too elaborate a bit more to get a more accurate answers.
Look up "Whale" manual bilge pumps maybe. They even come in a double action, pumping water on each return stroke. Reasonable price.
Recently being used on rocker box sluices. I think they get measured in liters per stroke off memory.
Unsure they they would work well for conventional sluice set ups. But might be suitable for fluid bed units like the gold croc.
Take some spinach out with you, end up looking like "POP EYE" by the end of the day!