Lighting wattage - how much is too much?

[Psyire]

Something else that should be mentioned too...

If you use a 14k or 20k bulb, the PAR will be lower and you can go without the VHO's. 14/20K bulbs in the 400w range have a PAR similar to 250w bulbs in the 10K range.

10K = White
14K = White/Blue
20K = Blue

(The aboves are the norm, but ofcourse they vary with company)

[Ruth]

The other thing that will make a difference is how far you have the lights from the top of the water. The higher you have them the less intense the light getting to the lower part of the tank.
The other thing you are going to have to watch is heat - those lights generate a lot of heat and can overheat your tank. It may not effect it too much right now but in the summer it could be an issue.