I did :smile: ... got 3 from the actually

Cheers

Thanks AJ.. I'll have to pop over and take a look...

Walter

I have been reading some books about marine fish, etc. and remain confused about the need for adequate lighting. The room where the aquarium is, is fairly light, but faces north. We have 3 large ?halide 175 W lamps with reflectors over a 420 gal. tank. As the water temp was continuing to rise (up to 83.7 F), I turned the lights off for most of the day. They had been on for about 12 hrs/day in cooler weather. The tank contains only fish and rock (prob. not live rock). Then I found that a floor fan aimed at the lights would cool the tank a bit, so I resumed lighting the tank for longer periods (about 6 hrs.) How much light does this tank need, and why?
A. Newbie

It likely only needs enough for the fish to be able to avoid swimming into things. Chances are you don't have any photosynthetic fish, so lighting isn't really important for your tank.
As diversity increases, such as corals, polyps, corraline algae, you'll need more light. What you have is enough for many photosynthetic organisms, and fish just don't much care!!