Very old thread but still very relevant. I've been out of the hobby for a couple years because of moving so much but I'm finally settled and getting back into it. Figured I would toss my opinion in on this subject. I voted for noon burst, and to explain why, I'll just going to repost part of a conversation I had with WolfenxXx a few years back:
Of course, there are other variables involved but light is the primary. No light- no algae.I feel like people are using far too much light for far too long. If I can make an analogy, it's like red-lining an engine every time you drive. You get to where you want to go quicker, but eventually that engine is going to fail. You may run out of gas, blow a gasket, throw a rod, burn off engine oil, crack the head, etc. There is a ton of problems that can come up if you are constantly running at very high RPMs in a car that was not designed to do so. Cars that were designed to do that, like F1 cars, have teams dedicated to maintaining them after every race or practice. It requires constant maintenance, and neglecting even one aspect will result in the entire system being unable to function. Similarly, I think with so many people using high light for eight and ten hours a day, it is almost a guaranteed catastrophe waiting to happen because of the constant need for maintenance. In many cases, this maintenance is specific to nutrients. I am not saying "no high lighting EVER," just in moderation. Similarly, it is good to almost red-line your car every now and then to blow out carbon deposits, etc. My bimmer gets red lined at least once a week (or near redline, at least.) My brother does the same on his Acura. I can also relate the lighting issure to weightlifting. If you lift hard for eight and ten hours each and every day, injury is all but inevitable no matter what supplements you add to your body. We grow while we sleep, and I think (I can't prove it unless it's already been proven) that plants do the same during non-photosynthetic periods.
I think a good discussion to start up would be the use of staggered lighting. Not the "siesta" BS that was all the rage back in the day, but better regulation/management of lighting intensities. Hopefully next year I will finally get my 50gal set up with a 24" Coralife Aqualight Pro HQI. That 2x65W plus a 150W HQI @ 10kK. That's a friggin ton of light!!! However, my plan is to run only one of the 65W bulbs for eight "viewing" hours (maybe ten depending on when I'm home) with the HQI turned on for maybe four hours in the middle of the day. Think about what happens in nature - the sun doesn't shine for eight or ten hours at maximum intensity all day every day. I do not believe high light = great plants. I think short bursts of high energy = great plants. If I'm not mistaken, Amano uses similar short, high intensity photoperiods on his tanks.