Does 2x65W = 130W when it come to lighting?

[jefflins]

Ok, I see a lot of talk about needing xx watts a gallon for lighting under different types of tanks. My question is, if you need about 4 watts a gallon (assumption for discussion) and have a 100g tank, can you use 1 400W bulb, 2x200w bulbs, 4x100 watt bulbs, etc.?

Also, does the Actinic count at 100%? That is, if I use a 4 bulb Aqualight at 2x65w 10k and 2x65 Actinic 65W, do I have 260W total? Or something less?

THANKS!

[reefrunner69]

Ok, I see a lot of talk about needing xx watts a gallon for lighting under different types of tanks.

Even with flo bulbs, WPG is not a very good way to light a tank, but it applys more to flos than MH. With different bulb types you use different criteria to determine what amount, spectrum and type of bulb to use.

[Biggen]

To go along with what Kevin said, WPG is pretty much useless in this hobby. It really on applies to FW so that you can get up or over the 1.5-2 WPG that is needed to keep plants.

It is much easier to decide what you want to keep (i.e. LR only, soft corals, hard corals, etc..) and then choose your lighting from those animal requirements. Don't worry about the WPG...

[loganj]

Another factor, and this applies mostly to MH bulbs, is the depth penetration. 1-400w bulb will penetrate deeper than 4-100w bulbs. A MH bulb is good for about 2' of tank...ie...for a 4' tank, you'd need two of them.
If you're using, for example, PC's...then you wouldn't really see a big difference between 2x65w bulbs and 4x32w bulbs assuming they are oriented the same way. It's best to go with the bulbs that fit your tank with fluorescents though. For example, a 96w PC is about 34" long...perfect for a 3' tank...two of them will span a 6' tank just right.

[jefflins]

Thanks for the feedback everybody!