"Sunlight Supply, in keeping with their commitment to provide grow lights using cutting edge technology, offers the Sun System Galaxy ballast".
The purpose of a ballast is to provide an initial voltage surge strong enough to ignite a lamp followed by a continuous voltage sufficient to maintain the ignition. Since the balllast is a heavy electrical component it is kept separate from the lamp/reflector and is connected using a high voltage cord. This is done in order to facilitate the raising and lowering of the lamp/reflector which could be rather diffiicult if the complete system were contained in a single unit. 150 watt, 250 watt, and even 400 watt systems are manufactured by Sunlight Supply that are light enough to be used as all-in-one systems although typically the 400w, 600w and 1000 watt systems have the ballast separated from the lamp/reflector.
Grow lights use two different types of lamps: metal halide (MH) and high pressure sodium (HPS), distinguished by the type of gas used inside the lamp. MH ballasts will work only with MH lamps while HPS ballasts will work only with HPS lamps. The most recent improvement with Sunlight ballasts has been the separation of components into their own compartment within the ballast casing. This allows heat sensitive components to be isolated from heat producing components, which further helps to prolong ballast life.
Sunlight Supply, in keeping with their commitment to provide grow lights using cutting edge technology, offers the Sun System Galaxy ballast. By applying digital technology to the requirements of modern high intensity lamps, they have been able to eliminate most, if not all, of the problems associated with traditional ballast including heat, noise,weight, and efficiency. Although the cost of a digital ballast is still higher than a comparable magnetic core ballast, it should be noted that the digital ballast allows the lamp (which represents one of the major costs associated with operating grow lights) to run brighter (15%-20%) and last longer. As lamps age, they lose lumen output. The Galaxy digital ballast has the ability to make up for lamp degradation by adjusting voltage flow to the lamp thus compensating for any loss of lumen output. (which for the grower means less re-lamping) Finally, the digital ballast uses igniter-less soft start technology, which avoids the harsh hard starts of magnetic ballasts that lead to a decrease in lamp life. When taking both lamp output and total lamp life into consideration, it is easy to see how some of the sting has been taken out of the initiial price tag associated with digital technology.
"Grow lights utilizing active air exhausting in conjunction with the use of tempered glass allow for an unprecedented amount of control over growing conditions that will help lead to greater yields"
Reflectors perform two basic functions: First, to maximize the amount of light received by the plants and second, to provide a way for the grower to control the heat being produced by the lamps. Two basic styles of reflectors are available commonly referred to as either HORIZONTAL or VERTICAL REFLECTORS. The horizontal reflector allows the lamp to be positioned horizontally inside the reflector while the vertical reflector allows the lamp to be mounted vertically. Since lamps that are mounted horizontally release more available light, horizontal reflectors have become the reflector of choice for most growers. No matter what the position of the lamp, however, a certain amount of light will end up striking the reflector above the lamp making the reflector surface a factor in determining how much light is going to be redirected downward.
Reflectors are usually made of either steel or aluminum. The advantage of aluminum is that it has a greater capacity to reflect light. The disadvantage is that it is expensive to produce. The best reflectors are made out of steel for structuaral support and then lined with a thin aluminum insert for maximum reflectivity. Steel reflectors without an aluminum insert are often painted white and produce fair results. Although aluminum is more reflective it must first be re-worked into what is referred to as a pebble finish in order to avoid its usual mirror like quality. The end result resembles an orange peel texture that produces a more uniform diffused pattern of light.
All vertical reflectors and some horizontal reflectors are constructed without the features necessary to manage heat and are used solely for reflective purposes. If heat is not an issue then these reflectrors are right for the job. If the grow room is located in an unusually warm area of the country or if the growing area is relatively small for the size of grow light being used then heat may become an issue. Many horizontal reflectors are made with vents on each end of the reflector where lengths of flexible ducting can be attached on either the intake or exhaust flanges. This flexible ducting will be connected to an inline fan which will actively carry away heat from the reflector to a remote location. The grower at this point has the option of letting the air being drawn into the reflector to be accessed from the room itself or from a remote source. When CO2 is being added to the grow room it is common to access the reflectors intake air from a source outside the grow room in order not to exhaust out any of the CO2 enriched air in the grow room
In addition to active air ventilation of the reflector one more step can be performed that helps to provide even greater control over heat production. Tempered glass will often be included with the purchase of grow lights produced by Sunlight Supply. This glass is mounted on the bottom of the horizontal reflector and acts to create a closed system within. This accomplishes two things. First it insures that no heat from inside the reflecor will escape into the growing environment and secondly, it allows the grower to lower the reflector much closer to the plant canopy without fear of burning the plants. Do not install tempered glass unless you are using an active air reflector exhaust system as this will cause overheating inside the reflector reducing the useful life of the electrical components and the lamp itself. Grow lights utilizing active air exhausting in conjunction with the use of tempered glass allow for an unprecedented amount of control over growing conditions that will help lead to greater yields.
"If you are growing a highly valuable crop
then re-lamping should occur at about the
one year mark"
Metal Halide (MH) and High Pressure Sodium lamps (HPS) came into use in the mid 60's as a way of covering large areas with relatively inexpensive lighting. They were later discovered by the agricultural community as a useful way of supplementing greenhouse crops and then as a primary light source for indoor gardeners. Metal Halide lamps tend to produce a spectrum that is better suited to vegetative growth while High Pressure Sodium lamps produce a spectrum more suited to Flowering. If a grower must decide between one or the other then HPS is the favorite since it can perform both jobs well plus the added attraction that it produces more useful lumens of light on a watt per watt basis than MH.
Growers wanting to maximize production will use SWITCHABLE ballasts in their garden which allows the use of either MH or HPS lamps. Sunlight Supply digital ballasts also have the capability of running either MH or HPS lamps. For the first month or two while the lights are operating from 18-24 hours per day MH lamps will be installed which act to produce a robust and vigorous overall growth in the plant. Once adequate size is established then the grower will replace the MH lamp with his/her choice of HPS lamps. The lights will be cut back to 12-14 hours and flowering will commence. If a grower is currently using a MH ballast but wants to provide the type of spectrum that a HPS offers there are now lamps available called CONVERSION lamps. When using a conversion lamp you are effectively either turning a MH system into an HPS system or inversely an HPS system into a MH system. The downside of this method is that the conversion lamps are particularly expensive plus the conversion lamps do produce fewer lumens compared to standard lamps. Is using a conversion lamp worth the money and effort? Since HPS systems tend to be better at both vegitative and flowering than MH systems it is more common for growers with only a MH system to want to use an HPS conversion lamp.
When the value of the crop being grown is high it becomes economically feasable to use lamps produced specifically for horticultural purposes as opposed to standard lamps The increased cost of the horticultural lamp becomes marginal when considering the resulting increase in lumen output along with the critical spectrum adjustment which ultimately leads to higher yields.
As a final note on lamps it should be pointed out that their output is rated in initial lumens. This is the amount of useful light that a lamp produces when it is new. As the lamp is used the useful light energy decreases and at some point the lamp will fail. The question for the grower is when to re-lamp knowing that the system may not be operating at peak capacity. The answer will be determined again by the value of the crop. If you are growing an inexpensive crop then re-lamping is less critical. If you are growing a highly valuable crop then re-lamping should occur at about the one year mark or before.