Reflectors are a waste of money, and Topsy Turvy Tomato Planters are not in any way dangerous.
Look at it from this point of view...Say your 600 watt HID gives off 95,000 lumens. One square foot of space one foot from the light source will receive roughly 7500 lumens. So if you have plants sitting under your light and you are reflecting all light down, how many plants can you fit one foot from your light? The reason I ask is because a plant two feet from this same light will only receive 1875 lumens, not enough....
Picture a point of light with a ball exactly one foot in radius extending around the point of light. This ball 1 foot from the light in all directions actually has a surface area of roughly 12.5 square feet. This means that you have 12.5 square feet of space one foot from your light source to use if you utilize the light traveling in all directions. How many square feet of plants can you put one foot from yor light if all your light is being reflected down in one direction? 3...4 square feet tops?
Let me show you what I mean. Look here, we took two 600 watt cooltubes and removed all of the built in reflectors that reflect the light down so that light can leave the cool tube in all directions. Remember, how close you can get your plants to the lights has a HUGE impact, and to only utilize one flat surface beneath a light is EXTREMELY inefficient. Light traveling up and hitting a reflector and then back down onto a plant that is already close enough to the light to get enough lumens is a waste, not to mention the power the light loses by traveling the extra distance to and from the reflector as well as the process of reflection. Light decreases by a factor of 4 as distance doubles, so getting as much plant surface as close to your light source as possible is much more important than gathering all the light from that source and then trying to throw it in one direction. When the plants go in, each Topsy Turvey planter gets a SCROG screen set in place below it, and every tote below done with hydro is done SCROG and each screen is dished towards to light source. Would you believe me if I told you we did 60 plants in a in a closet that is only 23.5 sqaure feet? Here are the pics how to do it. By the time everything was done we ended up with a giant oval surrounding the lights with an opening on either end to blow air through.
But hey, what do I know about reflectors.....other than by not using them (other than mylar) we can produce .94 GRAMS PER WATT.
I will admit that my point about using cardboard was stupid though, probably want to use a metal surface or something that will be heat resistant. But mylar will reflect just as much light as a reflector.
Give me a few minutes I will get a pic for ya....
Reflectors ARE a waste of money. Why would I buy a reflector that reflects 98% of light when I can buy a roll of mylar that reflects the SAME AMOUNT of light???? Besides, as I just explained, I don't want any reflective surfaces around my lights, I want as much plant surface area as possible.