MH bulb replacement

[queenangel920]

It's time to replace my 400W 10K BULB. I need to know how to correctly acclimate the new spectrum. Last time we did this, we didn't know any better and just changed the bulb and didn't adjust light time. So the tank broke out in major hair algae as a result. I do not want that to happen again. Do I start out at 1 hour a day then slowly increase it? How much and how soon? It's not possible to start the bulb up at a higher level and slowly move it closer to the water because it's attached under the refractor in the hood.

 

[bang guy]

would it be possible to place 5 layers of aluminum screen material between the bulb and the water? Then you can remove one layer a week.

 

[queenangel920]

That would be definatley possible but is that the best way? If it is, I could try it but it would be easier and cheaper to adjust the light cycle.

 

[tinyreef]

can you raise the fixture (i.e. tying up the pendant or spacers under the sides of the fixture). raising the distance between the light and the tank and gradually reducing over time gives the same effect as bang suggested.
multiple sheets of eggcrate also can accomplish the same/similar.