I'd go with a 36 LED kit, most people go with half white half blue but you can change that ratio depending on your personal preference. FYI half white/half blue using XR-E's would be about a 14k and using XP-G's would be roughly a 12k.
As for the heatsink, it depends on how high above the water you'll be hanging the lights but for a BioCube 29 we provide a 5.9" x 10" heatsink so something in that range would work for your tank.
I'd go with a 36 LED kit, most people go with half white half blue but you can change that ratio depending on your personal preference. FYI half white/half blue using XR-E's would be about a 14k and using XP-G's would be roughly a 12k.
As for the heatsink, it depends on how high above the water you'll be hanging the lights but for a BioCube 29 we provide a 5.9" x 10" heatsink so something in that range would work for your tank.