Growth Gas Generators burn propane gas. They are controlled by an electrical solenoid valve which in turn can be operated by a time switch to operate for just a few minutes in each hour, to give the correct amount of C02. "Threefold Enrichment" is a level widely used by professional growers during the hours of daylight when photosynthesis takes place.
In the air we breathe there is about 300 parts per million of carbon dioxide. If this level is increased to 1000ppm during the hours of daylight it is possible to speed up the photosynthesis process and thereby enhance the plant development. This is called "Threefold Enrichment". Some growers enrich their crop to 2000ppm, 3000ppm or even higher although this is not normally done commercially because of the economic viability of doing so.
Depending on the size of your greenhouse the Growth Gas Generator should burn for about twelve minutes in each hour to give "Threefold Enrichment" and will burn about half a pound - 1/4kg of propane in twelve hours.
