So it really has boundary ?
I had a small spider in one once that would set it off randomly. It took me a while to spot it and a while longer to get it out, since it was near the sensor and I couldn't just beat on it.
I purchased my grow light system from Spray-N-Grow Hydroponics. It's worked great for my lettuce.
5k to 6500 is a great light spectrum for seedlings and vegetation stages Don't fall below 5k or waste your time going over 6500 though As far as wattage, your plants will tell you if you need more if they start to grow stretched and thin stalked then add more light or move the light closer or try to contain the light with reflective materials With tubes you can keep them just inches from the plants and to insure no ho spots from bulbs keep a dan blowing on the tubes this turns the surface heat of the bulbs into ambient heat and the bulbs will be cool to the touch if a plant sprouts close to it while your not looking