I'm planning to get some LEDs from Rapid too. Which ones did you get? I plan to get their non-dimmable solderless 12 LED kit.
I explain my whole build in the link below,
I ended up going for the soldered dimmable LED since I knew I would be controlling the system with a Arduino micro controller. I knew I could make it tidier than the solderless kit. I also wanted to make use of my RGB LED strip, which would of gotten in the way of the solderless blocks.
Do you mind sharing the details behind your DIY controller? I am the midst of planning either a 20L shrimp tank or a reef and a DIY controller would help out.
I'm still in the process of cleaning up this project. I should have some more details in a week or two. I was planning on releasing schematics and design since most of it was taken from bits and pieces on the net. I just put them all together.