elos mini return pump upgrade ?

hi all, i'm researching a return pump for my elos mini system, and am stuck deciding what GPH flow rate would be most effective and ideal for my small stock sump.

i plan to "T" off the return line to push some flow back through a phosphate reactor (next reef shorty) which recommends a mini-jet 404 or 606 (rated at approx. 100-160gph). my current system runs an eheim 1000, that is close to running fully open at 250gph, with about 3.5 feet of return head flowing back into the main tank and minimal bends. i'm not really looking for feedback on pump brands, but rather ideal flows. the pump choices i have narrowed down are rated at 375 and 550gph at 3.5 feet of head. would higher flow be necessarily better? or something along the borderline of "just enough." the smaller pump runs at 35watts and the bigger at 48w. price difference is $20.

thanks all.