I'm trying to get an electrical design that I can put on a circuit board... I want either a, power on light on power off light off; power on two lights on power off both lights off; power on three lights on... all the way to 14 lights on then back down in reverse one light at a time till power comes on and no lights are on... then back up again. Now the other way I could see doing it is with a built in timer with memory where a light turns on every 12 hours till they are all on then back down... with the power cycling off for 12 hours at a time. If you can't have memory like that with the power cycling on/off your could do it in the circuits with 24/7 power on... one light turns on for 12 hours then turns off for 12 hour, then on with 2 lights and so on. (this would be for LED lights)
That's my Idea in a nutshell but it's already out there for about $300 with way more available customization of your entire tank... so ya.