Should use K2 star - Royal blue and CREE white. Mix them up at 2:10.
Try to research more before DIY as this could be expensive. Most importantnly, need to take of the heat generated by the LEDs, if the LED is running too hot, the light output will be much lesser. If not sure how to do it, just go and buy the ready made ones.
The initial cost of the lights could break even within 1.5 years, but will be faster if the electricity rates are increased again. 2 things you will save electricity when using LEDs. The lesser usage of electricity to power the lights for the same output of MH or T5s. And the LEDs do not normally radiate heat to the water, so the chiller will not have to work so hard. Therefore you will save on the electricity when running the chillers.