New lights

[naps]

Thats pretty bright for freshwater fishies IMHO. Compact Fluorescent lights are like 150% (or more?) brighter than standard T12 fluorescent bulbs. At 150% for example, your 260W worth of CF is the equivelent as about 400W of standard fluorescent lighting. That would probably be enough to grow most any plant even in twice the size of tank that you have (assuming the color temp is acceptable). Just a note, I had been using 4 GE plant&aquarium bulbs for about 2 years on my planted tanks. I think I read somewhere that they are only like 3500K or something. Seemed to work alright, but I have since upgraded to philips daylight deluxe bulbs (6500K I think) I have also overdriven them 2X so they put out about the same amount of light as a CF but only cost about $3/bulb.

So compact Flourescent bulbs are much different huh, so how do I calculate my wpg?? I was shooting for 4 wpg to have a good planted tank, with the CF bulbs what would I be at with (4) 65w in an 80g. And how do you get that number?? Thanks!!
I'm curious because I want to know what I'd be at if I bought 2 of those 55w CF bulbs that Tetra Freak pointed me too. Would that work better, to get less wpg so I don't blind the fish?? Thanks for the help again!!! :read:

 

[loaches r cool]

Ok, here goes. There was a post here a couple weeks ago title 'WPG rule updated' or something like that. Here is the basic reason why WPG is flawed. Wattage is a measure of how much electrical energy your light setup consumes from you electric system. Why would fish or plants care about how much electricity your using? Are they paying the electric bill? But if all the bulbs put out about the same amount of light per watt, then it works. Also alot of bulbs dodnt label thier actual light output (lumens), especially in the past, so we have adopted the WPG rule of thumb. However nowadays there are tons of different types of bulbs with widely varrying efficiencies.

Here is a link to a lengthy posting that explains alot of this: http://www.aquariumadvice.com/viewtopic.php?t=72491&postdays=0&postorder=asc&highlight=wpg&start=75

If you assume CF to be 150%-175% efficient as compared to standard T12 fluorescent then a 65W CF x 1.5 = 97.5W equiv. and 65 x 1.75 = 114 so an average CF 65W should be the equivelent of 97-114 W worth of T12 bulbs. Also remember things like depth of tank, reflector, and spectral output of the bulbs obvously change the usuable output of light that plants see.

Edit> There is a good page that goes into the details of things like Lumens and CRI rating, etc. http://www.aquabotanic.com/lightcompare.htm

 

[naps]

Thanks again!!

 

[b309302]

okay so if I have a 10 gallon with 2x10watt CF bulbs that say they are equivlant to 40watts each...am I running 2wpg or 8wpg? I never did undserstand that. Whatever it is the plants grow great.

 

[loaches r cool]

If a CF bulbs is approx 150%-175% more efficient than a standard T12, than a 10W bulb you could consider to be ~15W or so. Depending on the type of bulb, K rating, wether its a straight bulb or one of those twisty ones, if there is a reflector, the actual amount of usable light getting to your plants can very with all these factors. But at 150%, 2 bulbs gives you about 30W towards the WPG rule of thumb, which is a good amount of light for a 10g. Only the most light demanding plants might want much more than that IMHO.