I would think so. I run an 8 site UC with 8gal buckets and use a 1/10 hp active aqua chiller and it keeps my temps at 68. Other things to take into account are how warm is your grow area and how well is your UC system insulated from picking up the heat from your HID's. Before insulating my system and getting a mini split AC my room was about 85 degrees and my res was around 74, after insulating the system from light room temp was still 85 but res temp would fluctuate between 69 and 72. After installing a mini split room temp is now 74 and my res temp never moves from 68.
TLDR version....imo 1/4 hp chiller should work fine :)
