heating/cooling 34gal

[Chad]

Ok, quick question for those with experience..

With my 34gal cube I was planning on having the heating and cooling all done within my sump. I will have a max flow of maybe 150 - 160 gph being returned to the tank. Will this be enough flow to cool and heat the tank?

There will be a single 250w MH over this tank. probably a foot or so off the water. Also, flow is caused by a closed loop/ external pump. So not much heat entering the tank other than by the MH and at the same time, not much of a heating affect during the winter.. So.. thoughts? Will I need to do something else?

Thanks!