Marijuana Horticulture: The Indoor/Outdoor Medical Grower's Bible

don’t know is that many of the manufacturers buy and use the same components, often manufactured by competitors!
    Pulse-start metal halides commonly use 240 volts and harbor the starter in the ballast box, not in the arc tube. These systems employ physically smaller reactor ballasts that keep original line voltage within ten percent of the voltage in the arc tube.
    Reflective walls increase light in the growing area. Less intense light on the perimeter of gardens is wasted unless it is reflected back onto foliage. Up to 95 percent of this light can be reflected back toward plants. For example, if 500 foot-candles of light is escaping from the edge of the garden and it is reflected at the rate of 50 percent, then 250 foot-candles will be available on the edge of the garden.
    Reflective walls should be 12 inches (30 cm) or less from the plants for optimum reflection. Ideally, take walls to the plants. The easiest way to install mobile walls is to hang the lamp near the corner of a room. Use the two corner walls to reflect light. Move the two outside walls close to plants to reflect light. Make the mobile walls from lightweight plywood, Styrofoam, or white Visqueen plastic.
    Using white Visqueen plastic to “white out” a room is quick and causes no damage to the room. Visqueen plastic is inexpensive, removable, and reusable. It can be used to fabricate walls and partition rooms. Waterproof Visqueen also protects the walls and floor from water damage. Lightweight Visqueen is easy to cut with scissors or a knife and can be stapled, nailed, or taped.
    To make the white walls opaque, hang black Visqueen on the outside. The dead air space between the two layers of Visqueen also increases insulation.
    The only disadvantages of white Visqueen plastic are that it is not as reflective as flat white paint, it may get brittle after a few years of use under an HID lamp, and it can be difficult to find at retail outlets.
    Using flat white paint is one of the simplest, least expensive, most efficient ways to create optimum reflection. Artists’ titanium white paint is more expensive, but more reflective. While easy to clean, semi-gloss white is not quite as reflective as flat white. Regardless of the type of white used, a non-toxic, fungus-inhibiting agent should be added when the paint is mixed. A gallon of good flat white paint costs less than $25. One or two gallons should be enough to “white out” the average grow room. But do not paint the floor white–the reflection is detrimental to tender leaf undersides. Use a primer coat to prevent bleed-through of dark colors orstains or if walls are rough and unpainted. Install the vent fans before painting. Fumes are unpleasant and can cause health problems. Painting is labor-intensive and messy, but it’s worth the trouble.
HID Ballasts
    A ballast regulates specific starting requirements and line voltage for specific HID lamps. Wattages from 150-1100 use old-fashioned coil transformer-type ballasts. Smaller wattages– below 100–use energy-efficient electronic ballasts. Electronic ballasts run cool and quiet. Scientists continue to develop electronic ballasts for larger wattage HIDs, but the failure rate is still very high. It is very important to buy the proper ballast for your HID. Smart growers buy the entire HID system–ballast, lamp, socket, connecting wiring, and timer–at the same time from a reputable supplier to ensure the ballast and lamp go together.
    Be careful when purchasing ballasts that are made in China or Asia, in general. Many of these ballasts are poorly made and do not meet local safety standards. Do not be tricked by misleading sales phrases such as “all components UL or CSA approved.” Of course, each of the components could be UL or CSA approved, but when the components are used together to operate a lamp, they are not UL or CSA approved. Furthermore, chances are that if components are approved, they are not approved for the specific application. Cheap transformers, capacitors, and starters are cheap because they are of inferior quality.
    Do not try to mix and match ballasts and lamps. Just because a lamp fits a socket attached to a ballast, does not mean it will work properly in it. If you use the wrong ballast, capacitor, or starter with a lamp, the lamp will not produce the rated amount of light, and it will burn out sooner. The wrong lamp plugged into the wrong ballast adds up to a burnout!
    The “core,” or transformer, consists of metal