It drains back through the
pump when it shuts off. The overflow is only to keep the water from rising to high in the bottles.
Formula One from
Worm's Way - Gardening Products, Supplies, Service, Support, and Knowledge Base for all your hydroponics, indoor, outdoor and organic gardening needs, year 'round! is the best
nutrient solution I have used because you use it through the hole life of your plants. Change your solution if you detect a problem with your plants.
You have to vent the hot air out of your room from the
lights some how. Blowing hot air around your room won't do anything.
No fluorescents are useless unless used for seedlings.
One of each is best.