[hahnmeister]

Please direct me to the peer reviewed research that specifies “max of 700 for some yellow porites”.

Dana Riddle 2007. It took the most light of any of the corals he tested. Many others only took a fraction of that. The only organism that was higher (not saying higher light corals dont exist, only that they arent imported) was the crocea clam... it could take whatever you gave it.

As for the exact light output your home reef gets... it all depends on what you want to keep and how tall your tank is. The light levels at the bottom of a tall tank with 400 watt halides could be replicated by a 108 watts of T5s over a 10" tall frag tank. The light at the surface of the tall tank might be 700-900, and at the top of the frag tank, only 300... but in both cases, where the coral is at can still be 200. Thats why I found your suggestions ill-advised.

The other thing to keep in mind (not aiming this at you) is that our home aquaria are usually constant intensity over the course of the day. So calculating MegaMol/m2/day is what you have to do when comparing to nature. A constant intensity of 700 over 8 hours might equal the varying intensity that peaks at 2000 over the course of 11 hours. Comparing corals to what they get in nature seems to be a futile thing though... photosynthesis is all about a balanced chemical equasion. Due to lack of phytoplankton, flow, and other things... this rate will not be similar to what is in nature, so trying to match the light output isnt always the best thing either.

Most of the corals we keep are from 5-20m of depth where the PAR levels drop off very fast. Dana was nice enough to send me a full rundown of daily exposures w/ regards to depth of Corals, microMols/m2/s as well as MegaMol/m2/day. As it turns out, Im clearly overexposing my corals in captivity, yet my daily exposure is lower than what these corals most likely got in nature.

Lumens per square foot... why not just use the term 'foot candles'? Thats what it is. Its like calling a Newton a Kilogram-meter per second squared. Sure they are both right, but no need to make it more complicated.

I dont agree with this though...
"My point was “You have to be careful about lights that achieve high PAR by boosting the violet/blue spectrum at the expense of the rest. A balanced spectrum is needed.” For clarification I mean that high PAR can be achieved but by loading on violet/blue light and not paying sufficient attention to the rest of the spectrum. You have to look at PAR combined with light brightness (Lumen) to create a better aquatic environment. I am sure you have seen high PAR ratings which produce very dim lights. The light output does not provide enough spectrum or lumen to other corals that live higher in the water column."

PAR is the radiometric scale... what is important for corals and photosynthesis (they dont need to 'see', they just absorb the radiant energy). The photometric scale is not as accurate because it doesnt register blue as well... because the scale is based on what the sun makes as well as what our eyes see. But Radiometric meters dont 'boost PAR' by reading the blue levels unfairly... if anything, they are more fair than the Lux meters, since they are not going by what our eyes see... they are going by what the coral sees. I dont get where this comparison to the photometric scale comes from. PAR is the least 'skewed' measure for light around... it measures actual radiant energy, it doesnt measure it unfairly. Do you think photosynthetic organisms give a hoot about how we see the light? Not one bit. And since blue light contains more energy than red (shorter wavelength), it is important for us in this hobby to keep track of it with a PAR meter more than a Lux meter. Blue light can photoinhibit corals much worse than a warmer wavelegth. PAR, in most cases, is really all that matters.

PAR w/ regards to PUR might be worth comparing though. Dana has mentioned that perhaps his earlier review of the Solaris LED's, and putting a high value on the comparatively higher PUR:PAR ratio of the LED's vs other lights may not be the best thing. Too much PUR and too little PAR means the coral may not pigment in very well.