if your purpose is waterfall, my suggestion is use multiple pump
eg
if worker request 1 inch pump purchase 3 pump in size of 1/2 inch
(inform to worker before purchase because he need add multiple water lines)
plus point
available in many aquarium fish shop
replacement cost is law
you can use all pump in special and one pump in normal (save power)
but if your purpose is water flower, buy as it is to worker request