Old Bulbs = Algae

[Myka]

If everything else is in order, the bulb age and spectrum will have no effect on algae. On a tank that already has an algae issue a change in bulbs and/or spectrum can really help. On a tank on the brink of an algae bloom aging bulbs can be the straw that broke the camel's back.

My tank is a very good example right now. One of my 20K halides burned out. I only have 10K as spares. So my reef has a 10K on the left side (with 6 months use on it) and a 20K on the right side (with 14 months use on it). On the left side a minor dusting of diatoms shows up in late afternoon under the 10K bulb, but not on the right under the 20K bulb. Also, you can see a difference that there is more to scrape off the front glass on the left than the right.