Ok, I can certainly believe that

I had a quick look at a reflector with cooling tube and if I  am to add a fan and some ventialtion, it is starting to add up. I might as well buy a LED light then, possibly.

Or perhaps just use the 400w I already did ok with , without cooling.

I also dont know if a 600w HPS can outperform a "2000 w" (low cost) LED. I assume it does but I am not sure.