good day there eric8313, the pump size has a story.....
with my first cloner i tryed to use the Black Head misters....
i originally tryed it with a 150gph pump...
no go....
so went and got the 264gph pump.....
still no go....
so i went and got all Red Head misters and changed them out.....
with the 150gph pump it only drizzled outa the red misters.....
with the 264gph all the red misters work perfect, lol, shoots water like a foot out on ether side!

so....... to answere your question, lol, i think a 400gph might have too much presure for this small of a system, unless your Rez is gonna be like 3'+ under the sprayers, lift is the only thing i find the worst on preasure........

hope that helps!