Old Bulbs = Algae

[chris88]

You can't really compare Nm to kelvin. Red is from 650-700nm but that doesn’t correlate to a Kelvin tempter. A lower Kelvin light will have more red in its spectrum but that doesn't mean the bulb is going to look red. Just like a 10,000k bulb has a lot of green light, it doesn’t mean the bulb looks green. A 2,700k bulb will have a warm oranage-ish yellow hue almost like a candle light, while a 20,000k barely has any red spectrum in it and is predominantly blue. Most mid range bulbs have spikes in different spectrums which makes the color look white because of the way they blend. (6,500k – 14,000k)