New light bulb

[BROKER]

I just changed from a 400w 65k iwaski to a 400w 20k Radium over my 50. I did a 10% RO/DI water change using new cartridges before I changed the bulb. All tests read normal but I am getting spot green hair algae. I plucked out some macro from the refuge last night but that is the only thing I screwed with. Has this ever happened to anyone else before? Could adding a different bulb do this?

 

[tanzy]

Broker,
I don't know about green algae, but I have been fighting a dino bloom since I switched to MH from VHO.
It seems odd doesn't it that algae would rather grow under Radium and not an Iwasaki? How old is your bulb before the change?

 

[BROKER]

The bulb was about 11mnths old. I am guessing maybe it has something to do with the color spectrum but it really is a guess. I cut back feedings to the tank to every other day until I figure out what happened. I also plan on doing another water change this weekend. I had the brown diatom problem when I upgraded from PC to MH. I added more current to the tank and that seemed to help alot.

 

[Anonymous]

The change in color temp was probably the reason IMO.