Lighting question

[trevor30]

I just got back from my LFS and told them I wanted to upgrade my single strip light to a dual strip light. I had one 40 watt Power Glo bulb and now have two but they are not Power Glo. I am sorry that I can't remember the name of the bulbs but they told me and showed me that these are the bulbs they use on there planted tanks. My question is after replacing the hood the light output seems less then it did with the one Power Glo. Does this sound right?

[phanmc]

They sold you some of those purplish plant lights? Those lights usually has less lumen than full spectrum bulbs and the power-glo bulbs. It doesn't mean it's less useful for plants, but it won't be as bright to our eyes. However, return the bulbs if you don't like the look. The type of bulbs really isn't that mportant for plant growth, as long as you provide enough wattage.

[DevonBlaine]

the wattage could be increased - good .. but it looks like less light because it is in a lowere spectrum of color temp. If you look at the K rating it will give you the spectrum.

[trevor30]

Well, I went from one 40 watt bulb to two 40 watt bulbs. I told them at my LFS, The Aviarium, that I wanted to be able to grow what they had in there plant tanks and to set me up. Thanks for the info.

[RISK2123]

i wouldnt personally recommend "plant bulbs". i just get full spectrum bulbs for my tanks. i notice more algea growth when i had the "plant bulbs" in as cyanobacteria grows better with lower spectrum light. you may still get some algea but it def. wont be as bad. plus full spectrum bulbs (6700k) just have a better appeal to the eye.

[trevor30]

So then it would make sense to have more wattage but appear to be less light. That is what I wanted to make sure of.

[plah831]

yes, it's possible. Wattage is actually a measure of power needed to run the light, not light output. Lumens or lux are better measures of brightness of a bulb. But those are hard to gauge without a light meter, so most people use watts because it's more convenient.

But, for example, a T-12 bulb (that means a 1.5 inch diameter) that is 20 W can still be much dimmer than a T-8 (1 inch) bulb rated at 17 W. That's because the wider bulb results in more diffuse light. Also, individual brands will almost certainly vary in light output. There are complicated pages devoted to this discussion on aquatic plant forums, but they're over my head. I just gave you a summary from my own experience and understanding after glancing at those sites. Perhaps someone else will have a better way of describing it.

[RISK2123]

So then it would make sense to have more wattage but appear to be less light. That is what I wanted to make sure of.

yes definately, the spectrum has alot to do with it.

[trevor30]

The bulbs are Penn Plax FL 40's. Would you recommend these over the 40 watt Power Glo?

[twig]

my bulbs are borderline freshwater at 10k superdaylights and they are OK. They look a bit different though ...

[trevor30]

A little off topic but wondering if anyone might know where I could find a glass canopy for a 52 gallon flat back hex?