You didn't say whether your Zone VI Cold Light has the built-in photocell. The older ones did not, but the newer ones did. If you have the built in photocell, I would recommend the Zone VI Compensating Enlarging Timer from Calumet. It's not cheap at $380. If you don't have the built-in photocell you can get one from Calumet for about $55, but you will have to install it yourself.(posted 8059 days ago)There are two main considerations with cold light heads and timers. First, many digital timers cannot handle the load, and second, you need some way to stabilize the light source (which is notorious for fluctuating). Zone VI Compensating Enlarging Timer and photocell solve both of these issues, but there may be other solutions.