Metal Halide vs Mercury Vapor lighting?
 

Hi Ron! Great site!! What's the difference Between Metal Halide and Mercury Vapor lighting? would Mercury Vapor work well enough for veg. growth? appreciate any info you can give on this? also, I have Built your 11 plant Garden, and have recently transplanted my first Crop. I notice that the lower leaves are turning yellow. Is this a nutrient problem? I am using Hydrofarm Bloom/Grow at 1 tsp/Gallon in my 7 gal res. my pump runs for 15 min. every 2 hours and my lights are on 18 hours.

Mercury Vapor puts out the wrong light spectrum for growing. And I don't know enough about plant growing to know why my plants don't turn yellow and someone else's does. When in doubt dump your solution and mix up a new batch.