3R Lighting/Tutorial: Metal Halide or High Pressure Sodium Grow Light

How to tell the difference between Metal Halide and High Pressure Sodium Growlights.

How to tell the difference between a Metal Halide Lamp and a High Pressure Sodium Lamp continued

Now, another word of caution, it is not uncommon for some people to put the wrong lamp in either the wrong type of fixture or the wrong wattage fixture.
Replacement lamps are not inexpensive and some folks think very short term. Sometimes the wrong lamp will work for a while, but soon the lamp gets eaten up and long term the components inside the fixture will fail. A qualified service technician can repair or replace the internal ballast components but this costs, too.

Other folks figure that they can save money by screwing a 250 Watt lamp into a 400 Watt light system. This will really screw up the lamp and the fixture.

When a lamp is manufactured, each one is stamped with a code that tells what it is. Here are some common abbreviations and what they mean:

HPS-High Pressure Sodium;
MH-Metal Halide;
MS-Super Metal Halide;
HOR-Horizontal (made to burn only in a horizontal position;
BU-Base Up (made to burn in base up position only);
U-Universal (burns in any position);
LU-High Pressure Sodium.
There are many more, but these are the most common.

Click here to download pictures of Metal Halide and High Pressure Sodium Lamps.
These are high resolution pictures so they may take a while to load.

continued on next page