[Ross]

Light meters (mostly) do not measure color of light (Kelvin) but they measure light intensity. I was very frustrated trying to figure out what my meter was telling me when I had an inexpensive one. I bought this one: Sper Scientific Light Meter Lux & Foot Candle | Sper Scientific but they have a foot-candle only version for less. I like it because it calibrates itself every time you turn it on, so it knows true zero. There are scales, but you just hit the scale button till something reads on the screen. Quite simple and highly accurate. The most important reason for owning a good meter is to take a reference reading at a certain distance from the fixture and subsequent readings to determine when the tube is fading over time. Don't rely on your eye alone.