I would think the white supplemented with the magenta would be the best choice. I use the last button under the blue group. The only problem is that I have my lights on a timer and when they come on in the morning, they revert to all white, so I have to add the magenta each morning. I have heard some people say the Flex lights don't work on a timer, but I am using a mechanical timer and they work fine, other than reverting back to all white. I just bought a digital timer marked 'cfl/led ready', and I am going to try that one today. I have had my 9 gallon Flex set up for a month and things are going well so far.