Healthy?

looking good, very healthy IMO. Now would be a good time to LST them if you where thinking of it. If by white spots you mean the stuff on the tips of the leaves, might be from to much feed or to much light. If you spraying anything on them then that could be contributing to it. When the tips of the leaves point up and bend like a taco shell that's a common sign of to much light or heat. May want to try raising your light up to 50cm/20" from 45cm/17" and increasing the airflow to see if it helps with anything. Sometimes white spots on the leaves can be from pests but they look different and not like the ones your showing. I do see lots of yellow sticky traps. great for monitoring of pests but they don't do much in terms of controlling them as they all tend to have completed their breeding and egg laying cycle by the time they get on that trap. I would recommend BTi or nematodes for gnat control both are tried tested and true methods of killing em dead with no harmful side effects. Good Luck!