Soon I'll be ready for my first test run. When I test the operating temp should I use the MH or the HPS or should I test both for a full cycle?
i think that would depend on the situation.......if you are veggin plants the MH is better....and you should keep the HPS for when you are flowering......
I assume you'll be using both to grow so I would test both but I doubt you'll find much difference. They both put out a crapload of heat.
One of the main reasons you'll want EVERYTHING in the room to be white is that they both put out a whole lot of infra-red. I think the HPS more than the MH. Anything dark colored is going to absorb that infra-red and get warm or hot, depending on how far from the lamp it is. Definitely test both.