Having pump problems Tom?
Did someone mention, Aussie?
Tom, it is not huge but there is a perceivable improvement in performance if you run a pre- pump.
My thoughts on the size of pre-pump, as long as it supples positive pressure on your system, greater flow than your pressure pump draw
The main reason that I run a pre pump/bilge pump to supply my machines is that I use large 10 micron inlet filters.
You need positive water pressure on these filters or they will suck air.
Any problem running them continuously?