no sump... no worried.... have a pump drawing from your overflow to feed your skimmer on its own dedicated loop. Just be sure to keep a very(!) steady water level with daily evaporation top off (I highly suggest you automate this).
If no skimmer, do be sure to go heavier on water changes, lighter on bioload (stocking, feeding), consider a refugium for nutrient export, etc.
regardless... a small submersible Mag drive pump can sit in the tank separate from the overflow box and feed the manifold.
Anthony