I'll take a look and see if I have a log from that tank. Almost 30 years ago so I doubt it, but I do know phosphate would be high by today's standards (0.5 ppm, as estimated by a LaMotte visual comparator.) There would be a definite decrease in light - I had to wire two VHO actinic lamps into a Coralife metal halide luminaire because in those days it was either/or halides or fluorescents. So, I decided to try just the VHO actinics under the mistaken belief that blue light's higher energy level made a difference in rates of photosynthesis.
Interesting. Please keep us posted!
It just occurred to me that I have (maybe) a second incident to report. My lab's tank is 3 months old and has had minimal dinoflagellate growth for a while (rock exposed to light had a slight fuzzy brown appearance and glass would get a haze.) I purchased eight corals on November 8 and placed them on a frag rack at the bottom of the tank. Wanting to give them more light, I added a LED strip light and ran it for 4 hours a day (2 hours a.m., 2 hours p.m.) The dinoflagellates bloomed and formed snotty brown threads. Nutrients are 0.01 phosphorous and 0.7 nitrate as N (about 3 ppm as nitrate if my early morning math is correct.)
I presume Phosphorus and Nitrate levels didn’t change once you added Corals, and the only change was the additional LED strip light?
No changes in water chemistry to speak of since adding the LED actinic strip light (NO3-N went from 0.9 to 1.0 ppm; P remained at 0.01.) LED strip has been removed.
I’ll be very interested in hearin what happens to the tank now that the LED strip is gone.
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Fair enough. However, if (speculating) the tank is dry rock cycled, no fish, no N and P source, with moderate filtration, hitting that correct spectrum would cause an increase of N and P consumption from coral. When those numbers hit low in a new tank and its been exposed to dinos from frags, you've created a dino environment.The discussion is obviously not that LEDs cause Dino blooms where MH and T5 don’t. The discussion is whether or not spectrum plays a roll, and how much of one.
I don’t think it’s out of left field for that to be theorized... spectrum plays (clearly) a huge roll is zooxanthellae propagation, and since zoox are a type of dino, this certainly seems plausible. Looking forward to hearing what happens.
90-gallon with a 40 gallon sump. Dry rock. CaribSea Fiji Pink live aragonite sand plus perhaps 10 pounds from a fully cycled tank. Reef Octopus skimmer, GAC, filter socks for mechanical filtration. Tank has been up and running since late August. Correction - eight frags were added on 11/1/2017 for a total of about 20. Frags purchased on the 8th were not added and are in quarantine. The only thing that changed was the additional lighting (and the frag additions 0n 11/1.) I should be careful in implying that lighting was the causative agent (the title of this thread is after all a question.) What I can say is that I've seen blooms when lighting was drastically changed to the blue end of the spectrum (intensity rose in one instance and fell in the other) but can't point to a specific cause. Anecdotal at this point based on my and one other's observations (with a couple of maybes.)
