Lighting

[brianfl]

I currently have a 120 deep (24" depth). It is lightly planted. I currently have two flourescent light packs each with two bulbs. So I had been running just one of the packs (240 watts). I noticed some of my plants (sword plants) getting a little yellowish. So I have turned on both packs (480 watts) and now the top of my two tall plants (not sure of the name) were getting a little reddish brown at the very top (burn?). The lights do seem pretty hot. The fish seem to like the 240 wattage better than the 480, I have a few balas and some dwarf gouramis and a pleco.

Is it necessary to have 4 watts per gallon for a deep tank or does the depth make that much difference? I basically have two watts per gallon in my 55 and have had very nice looking plants. Ironically, I have pretty much the same plant types in both tanks. Also, would it benefit me to get cooler burning bulbs? I have just the standard bulbs.

I am more interested in the fish being happy than the plants and they were a lot mellower with the 240 watts. Any suggestions?

[djlen]

It really depends on your preferences. You said that you were fine with plants that did well in 2watts/gal. so why go higher. You can always add wattage if you want, eventually, to get red plants or other plants that need more light. Also, when you go to a higher wattage you increase the need for balance in the tank. CO2, a good balance of ferts. and traces. And 4watts/gal. is a load.
One other thing. Your new tank, at 24" is only 3" higher than your 55 which will make a moderate difference in light penetration, but I wouldn't think it is a big deal in a low/moderate lighted tank.
Make your choice on the plants and tailor the light to them.
Len