A 5/8 hose is fine if your pressure is adequate. If pumping from a distance (>200 feet) use 3/4 hose, or bury a 1 inch or larger line to avoid pressure drop (which kind of defeats the purpose of this product). I have a 500 foot run with 30 foot rise using a 1hp pump and can run 2 sprinklers at once, but not 3, using 4 100 foot 3/4 inch "farm/contractor" hoses to get to my Y connector.
