The bigger ones are Gavita 1000W DE Sodium, very powerful lamps more to the red end of the spectrum. They do most of the work.
The smaller ones are Hortilux, I think Ceramic metal halides with a very high colour rendering index which serves as supplementary lighting to give them the other parts of the light spectum they need.
Nothing to do with heat.
I work in the industry (though I think most of our end users grow a different kind of grass)