Cfl Bulbs... What's My Watt Per Gallon? :s

[Channti]

Alright, so I checked out my lighting fixtures in my tanks, and I picked up some regular CFL daylight bulbs from the hardware store.

the box I have is labelled 6,500K output per bulb, 11 watts each. I have two bulbs in the 5 gallon tank.

I feel like i have too much light. Does this mean I have 11 watts of light (therefore 2.2 watts per gallon) on the tank, or 22 watts on 5 gallons (therefore 4.4 watts per gallon)?

They also had a 2,500 K output bulb. Would Two 2,500K output bulbs be better?

I'm afraid I'm going to fry the plants in my tank.

 

[Katty]

The watts per gallon rule doesn't really apply as well to small tanks. For instance, you can put a 2 watt light over a one gallon tank, but you wouldn't have enough light anyways even though it fits the watts per gallon rule. Small tanks actually need more than 2 watts per gallon to grow the more demanding plants. I'm sure someone else can explain it more thoroughly though. And no, picking a different K bulb isn't necessarily the best option because it gives off a different spectrum of light, and plants need particular wavelengths of the spectrum to grow properly.

I don't think the bulbs would kill the plants unless you're doing low light plants.

 

[Channti]

So what kind of plants should I stock in there? Mid to high light plants and avoid the low-lights?

 

[Katty]

I think you could stick in the low-to-midlight range for plants. Come to think of it, I don't actually know any low light plants that don't like or tolerate medium light (unless someone cultivated underwater mushrooms...), and I don't think your tank quite classifies as high light despite the 22 watts. Hopefully someone with more experience can clarify on that.

 

[Channti]

Alright, so I should be good with my cuttings then. I've got a little more than half a watt per gallon in my 46 gallon, so I should be good using cuttings from it.! thanks a billion!