Type of light question

[garnpet]

Would there be a difference between 100 watts of  compact flourescent lights and 100 watts of a regular flourescent light, or is 100 watts of either going to give you pretty well the same result in a planted tank?

(Let's assume the K rating is the same on both types of lights)

[BigDaddy]

Depends on the size/depth of the tank in question.

But the CF bulbs will provide you with better growth than their NO equivalents, all other things being equal.

[garnpet]

The reason for asking is someone is looking to put 6-26W bulbs over a 125 gallon tank in the hopes that will be enough light for a planted tank.  That's just over 1 watt/gallon and I am assuming it would not be enough for a planted tank.

[BigDaddy]

The WPG "rule" breaks down on larger tanks.  Even still, that's only enough light for low light plants.

26 Watt bulbs?  We aren't talking about the spirals are we?

[garnpet]

They are not spirals, but I'm not sure what type they are, perhaps something more in the industrial mode.

The questions was more asked to determine if the same amount of wattage for the CF bulbs was brighter than other types.  I think it is pretty obvious that either way that this person would not have enough light for a planted tank, other than some of the low light plants.

[BigDaddy]

The thing to be aware of is that six 26 watt bulbs will not provide the same energy as say two 55 watt bulbs.  The problem being that a 26 watt bulb simply doesn't produce a lot of light energy.  Then, add the fact that a sizable percentage of that light is lost at the water's surface, and you have a very poorly light tank for plants.

It is always better to get the largest single source of light you can instead of several smaller sources.

[kennyman]

look for the lux ratings on the packages.