If its gonna be a sump/fuge then I'd say no. The impact a fuge that small will have on a 140 will be minimal. If it were just a sump though then yes you could do that. I would reccomend a refugium of atleast 15-20 gallons on that size system if you want it to really have any effect. Bigger the better though so if you can go even larger. Imo
the best setups the sump/fuge systems hold more water then the actual displays.