Not so young in age but young grower. I am on my first inside grow.Youngster!
MH= Metal halide. Think of bright white parking lot lights. HPS= High Pressure Sodium. Think of those yellow parking lot lights. Trust me, you can grow some really nice dope with 'em. Mine are in a cool-tube with forced air ducting drawing cool basement air in and exhausting warm air out into my cooler basement. At this stage in my life, I can't justify joining the LED crowd and scrapping them.