Need lighting help

[Douglas]

I need some help with my electrical lighting issue. My tank has been running since last May. Now,when my metal lights kick on, the breaker pops. I have 2x150watt metal and 4x54w t5's in my giesemann light. The T5's turn on, and an hour later, the metal lights try to turn on, and the whole breaker pops. Shutting down the whole tank. The only thing that has changed electricaly was the reduction of the heater size, from a 300w to a 200w. Everything has been running fine since last May. Everything is on one electrical circuit, pulled just for the tank.