Reeflow pump/water change question?

[Lampshade]

I have reactors hooked up to my main pump, when i target feed i open a bypass that dumps my return right back to my sump. it drops the pressure low enough that there's no water reaching the tank, but still keeps some(minimal) flow through the reactors. Works enough to keep my bio-pellets from blowing up when i close the valve. Might be an alternative for you.