Reply to Studio Monitor Question

I've had the Alesis M1 Active 620's for about 5 years. They're loud and crisp, but I'm dealing with the "blue light of death" for the 3rd time on the pair. When I soldered a new capacitor in again, I burned and lifted the trace. Honestly, I don't feel like paying the money to have it repaired and want to go in a new direction. My back up monitors are Blue Sky's. They're really accurate and nice. However, I use my monitors for production and dj'ing, so I want lots of low end when I DJ. How are the KRK 10 subs? I can snag a used one for about $200. Would I be better off with some Rockit 8's or the Blue Sky's with the sub? Any suggestions? I really just want it for dj'ing. I play drum and bass, so dnb without any low end is pointless. I probably wouldn't use the sub to produce. I've had problems with my mixes being way too subby in the past with a dedicated subwoofer.