A) I never said or even implied that I,"want a single answer that applies to every situation...". You are now putting words in my mouth and that's not fair. I don't mind having a disagreement and discussion. But lets not start fabricating and exaggerating.
But that's what it means to dispell a myth. Are you saying that it might happen sometimes and not others? If that's the case then we are in total agreement.
B) You now say, "It's one of those things that has just a grain of enough truth in it that we can't 100% call it a total myth." So now the idea that old lights are a contributing factor to algae growth,"has just a grain of enough truth..." and , "we can't 100% call it a total myth."
That's what I've been saying all along. The effect is not a total lie, it happens. But it's not the end of the story. How do you think this all comes down to lights? How can you say it has nothing to do with lights? You can't make either assertion. If you don't think lights contribute to algae growth, then turn them off for a week and see what happens to your algae.
I'm more than willing to buy that level of association between old bulbs and algae growth. Now the question is, is it really worth the expense of new bulbs every 6-12 months to avoid what; 1)has a grain of truth, 2) isn't 100% myth, and 3) may not even happen if you have your nutrients under control?
Man, you still don't understand me. I don't think you have to change bulbs every so many miles to avoid algae. I do believe that an algae problem CAN BE related to spectrum. I'm not basing that on anyone's study about fish tanks, I'm basing that on the light harvesting complexes present in the algae and the absorption spectra of those complexes. I've given you information on that. Would you like something more technical?
New lights over my 2 tanks would cost well over $500 if I buy quality bulbs, and about $250 if I buy cheap. Why should I spend $500+ for new bubs just because there is a chance some algae may grow? Heck, I can change $500 worth of bulbs and algae may grow anyway!
And you are absolutely right. No one said change the bulbs or algae will grow. Why would you change good bulbs? That would be stupid. What was said was, if you can't get the algae under control, look at the bulbs. Sometimes it helps. It's not going to make the problem go away on its own, but it may help you get an edge on it. I don't see why you don't understand the difference between a cause and a contributing factor.
I mean really, by all means, wear the bulbs out. If you get algae, then kill it it's not hard. If you don't then cool no problem. None of that means that color spectra has nothing to do with algae growth. It's a photosynthetic organism. Light affects it. No doubt.
Similarly, why do we run blue lights over our corals and not yellow? Because the coral prefers it. I think we know for a fact that the coral grows better under the blue. Right? So how is it so hard to believe that there also exists species that like red? Terrestrial plants for one. Why do you think leaves look green? It ain't cause they're absorbing green light that's for sure.
I understand that you believe that the spectrum shift in older bulbs is a contributing factor to possible algae growth if the nutrients are there as well. And that is in no way an unreasonable position. But your believing it, doesn't make it so. In fact, I would suggest that if it were so, somebody (like a bulb manufacturer) would do a study to prove the point. It sure couldn't hurt their sales. But there aren't any studies that prove that belief. OK, there may be such studies, but I haven't seen them. Have you? Has anybody?
