Hey Slothy,
I have an Ice Probe mini chiller by Coolworks that I used on my 46 bow and it gave me a 5 degree pulldown(maybe a little more). I Highly recommend it. It was hotter than Saddam's living room here in NY last summer and it got me through it by maintaining 81 degrees all summer. The tank was 86-88 without it! I only had 440 watts of VHO though. NO MH's.I drilled it through the side of an aqua clear 500 filter.