There isnt much space. If you work out a way to fix them there will be just an inch, perhaps slightly more between the LED and water.
My original idea was to somehow fit them whilst retaining the stock canopy. But aside from fitting them in such a small gap, you have to factor in heatsinks and a fan to cool the LEDs.
So, I have about 12 Royal Blue LEDs on order from RapidLED. I will probably end up using only 8-10 on one driver. I am going to build a completley new canopy. I want to retain the halide as I've customised that to run off an ectronic ballast (see my post many pages back) and because I dont completely trust LED's for overall coral growth.
I should recieve my LED's sometime this week from USA. I wont be able to start the new project until many weeks later.