I had 6500k bulbs over it...
This is something that I learned recently. It turns out that K value is just the color of the light bulb. It does not represent the spectrum of the bulb. If you look at this image from
http://en.wikipedia....lor_temperature , you'll see what I mean:
http://upload.wikime...-comparison.png See? The K value is merely how yellow or blue the light is, what color it is.
This, on the other hand, is a light's spectrum:
http://www.fosterand...ctrum-graph.jpg That image came from this website, where the bulb is particularly advertised as a plant grow bulb:
http://www.fosterand...cfm?pcatid=4505Notice the peaks in the blue and red regions of the spectrum. These peaks and the wide distribution of light at many different wavelengths are important for the plant to be able to get energy. It is possible to create a 6500 K bulb without having a peak anywhere on the spectrum except a few points. Such a bulb would appear like it's good for plants, but if the plants can't access the energy at those few wavelengths, then they won't be able to grow. *nods*
I understand the rest of your plants were growing well. Personally, I've found that Ceratophyllum demersum is more affected by inappropriate light than other plants. I put some of that beautiful healthy hornwort you saw in that picture in my previous post into a 10 gallon tank with a low bioload and 'cool white' bulbs, and all of the plant tissue too deep in the tank to access sunlight died and rotted. The stuff close to the window remained bright green, so I think it was the 'cool white' that killed the rest of the hornwort.
...
Also, here's an ID guide for Myriophyllum spicatum.
http://plants.ifas.ufl.edu/node/278 It matters because of this:
http://www.sciencedi...043135400000397Myriophyllum spicatum-released allelopathic polyphenols inhibiting growth of blue-green algae Microcystis aeruginosa
Satoshi Nakai, MCorresponding Author Contact Information, E-mail The Corresponding Author, Yutaka Inoue, Masaaki Hosomi and Akihiko Murakami, M
Department of Chemical Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka, Koganei, Tokyo, 184-8588, Japan
Received 1 April 1999; accepted 1 August 1999. Available online 18 May 2000.
Abstract
A culture solution of macrophyte Myriophyllum spicatum was subjected to algal assay-directed fractionation on the basis of polarity and molecular weight. As the water-soluble fraction below molecular weight 1000 was the only fraction to inhibit the growth of blue-green algae Microcystis aeruginosa, it was analyzed by analytical high-performance liquid chromatography (HPLC) and atmospheric pressure chemical ionization mass spectrometry (APCI-MS) in order to identify M. spicatum-released growth-inhibiting allelochemicals. Both HPLC and APCI-MS revealed the release of four polyphenols exhibiting growth inhibition effects, i.e., ellagic, gallic and pyrogallic acids and (+)-catechin. A quantitative investigation of their respective inhibitory effects showed that (1) gallic and pyrogallic acids are more inhibitory than (+)-catechin and ellagic acid, and that the autoxidized products of each polyphenol demonstrated growth inhibition. Finally, when the collective activity of a mixture of the polyphenols was examined, synergistic growth inhibition of M. aeruginosa occurred.
Edited by EricaWieser, 30 August 2011 - 07:10 AM.