My first DWC grow~~~~OG Kush

so heres my first DWC grow....
-OG Kush
-DWC 18 gallon rubbermaid homemade system with 6 in. net pots
- 2- 600 watt hps hortilux lights
-canna nutes

Im exactly 4 weeks since i changed to 12/12. they seem to be growing good. vegetative growth slowed down and now the buds are swelling.
what do you guys think?
do they look good for 4 weeks?
how do the size of the buds look? do they look normal for 4 weeks? i feel like the growth has slowed down but maybe its just the vegetative growth?
one thing thats bugging me is today i noticed the reservoirs were half empty and i filled them 3 days ago. some of the roots looked like they were drying out.
how full should i keep the reservoir?
should i worry about my yield since the roots were drying out?
they plants look super healthy...
any opinions would be appreciated.
thanks

Looking good dont worry to much about your yield.Your plants look fine.As for the water level try to keep it two to three inches from the bottom of the net pot.Your plants should start aggressively growing after the fifth to sixth week. I dont know how much nutrients you are applying but not try to go full strength go for about 3/4. OG'S cant handle much nutrients.Good luck and keep up the good work!