This is really complicated. Lots of different types of algae out there. Lots of different water conditions and plants. My guess is that bright light with plants that can take advantage of it will help control algae. Do this with plants that can't fully take advantage of this and algae may gain the upper hand.
Originally Posted by MatPat
Wasn't the WPG rule created a long time ago when T-12 lamps were our only source of lighting for planted tanks other than incandescent bulbs? T-8 lights have now replaced T-12 lamps in most commercial strip light fixtures today. T-8 lamps give us more intensity per watt when compared to T-12 lamps. How much do we decrease the original wpg rule for the greater intensity of T-8 lamps?
This is my personal crusade on this forum.
Repeat after me, three times: "WPG is an estimate, not a rule."
My rough calculation is that WPG is +/- 50 percent considering tube technology (efficiency), tube spectrum, and reflector.
Compact Flourescent lights are a big step up from the T-8 lamps in intensity per watt yet people still use 3+ watts per gallon with these more intense sources of light.
My 2nd personal crusade on this forum is that Compact fluorescent lights only make sense for tanks less than 24 inches wide. Linear tubes, whether T8, T5, or T5 HO make much more sense for tanks wider the 24 inches wide. This is due to three factors.
Factor one is that power compact tubes are bent in a way that sends light back into the tube. This means that reflectors are basically crippled with these lights.
Factor two is that the ends of fuorescent tubes don't produce as much light, so really short tubes don't produce as much light. So this technology is appropriate where you would have to use a really short tube because of limitation of physical space.
Factor three is that aquariums tend to be rectangular. Therefore, it seems totally insane to me to have 48 inch compact flourescent fixtures when T5 HO produces a little bit more light per watt than compact flourcent lamps and can have much better reflectors. T5 HO also work better warm and don't need (the wasted energy for) a fan when the fixture is designed properly.
Do we need to decrease the WPG rule more to take this more intense light source into consideration? How much more intense are PC lamps..are they double the intensity of T-12 lamps? |
Should the WPG rule be decreased even more for linear T-5 lamps and if so, by how much?
Yes, there are some tables online for this. You will probably like this http://woo.gotdns.com/Aquarium/CalcL...h=18&Length=48
What makes more sense to me is to come up with a scheme to modify lumen/lux watt meters. Need to fliter out the UV and infared to get something close to PAR, then notch out the green. $100 for the light meter, $100 for the filter is my gut guess. May only make sense for photographers who have other uses for the filters and meter.
I believe the linear T-5 lamps are an even greater increase in intensity over the compact flourescent lamps since they have less restrike and possibly even better reflectors.
In order of efficiency of lumens/watt:
Power Compact *
* I have a spiral twist hydrobulb that claims to be better than metal halide, but provides no proof for this on the bulb package
The fertilization methods have changed greatly since the WPG rule was developed why not revisit the WPG rule also?
Repeat after me...
With the greatest respect, but can't help being fanatical when people want to use rough estimates as absolute rules.