Hair Algae growth under different lights?

[Fanof49ASU]

Instead of hi-jacking nighttimenick's thread, I thought I'd start a new one based on a reply.

<a href=showthread.php?s=&postid=14242796#post14242796 target=_blank>Originally posted</a> by DMBillies
I've read quite a bit on this actually...

Scientifically speaking, high magnesium should slow photosynthesis and hopefully slow hair algae down a little based solely on the photosynthesis reaction.

That said, Kent seems to be the magic bullet in terms of keeping Mg high, so I'm guessing that it has some type of trace element in it that most other Mg supplements don't that is increasing effectiveness. If I were a big corporation and heard about this, I would be pouring money into trying to figure out what the difference is.

Just curious.......did it say anything about different lighting......some causing more hair algae than others?

Right now (due to funds), my lighting is piece-milled. I have 3 separate lights on top of my tank. (2) 24" T5's that give a really clean, white light and a Coralife quad (96w with an old bulb) that has a strong yellow cast. I have two return nozzles on each end of the tank. The return under the coralife has 'some' hair algae, but the nozzle under the T5 is completely clean. (There's no algae growth on the rocks or anywhere else).

Off topic.......this is really odd......the coraline is really growing well under the pc's....even on the sand, but not nearly as plentiful under the T5's.

 

[DMBillies]

If I had to guess, what your seeing with the coralline is a result of different light intensity as opposed to the spectrum type.

In my experience, coralline actually grows quite poorly in really high light areas and a return nozzle is probably getting blasted by light under the T5's.

Now, as I remember according Sanjay, the intensity of light in the photosynthetically active part of the spectrum is what is important for corals, not the actual spectrum (i.e., blue light that has the same PAR readings as yellow light will grow things the same). I assume the absorption of light for plants works on the same principle?

If that is the case, then the color shouldn't really matter and we're back to it being a light intensity issue. I know most of my hair algae problems started low in the tank as well. It seems weird that more light might prevent algae growth, but at some point it is possible to overwhelm the algae and bring on photoinhibition (for those who don't know, it is basically the point at which there is so much incoming energy that it cannot be used and that additional energy starts to damage the plant).

If that photoinhibition point is slightly lower for some of these algaes than it is for the corals we're keeping (which I'm sure it is for at least the light loving SPS), then in theory it is possible to have a thriving reef that is resistant to algae growth. In practice there would be many reasons to not try adjusting your lighting to fix algae problems.

The exception, IMO, would be replacing old bulbs. The point I made above seems the most plausible explanation for why some people start to experience algae problems when they are using older bulbs despite everything else remaining fairly similar (the light levels drop below the photoinhibition point in larger areas of the tank and algae has more of an area to get a good foothold).

I am of course making a few assumptions about things I am not an expert about so don't take this all as fact and I do hope someone will correct me if I am wrong.

 

[Fanof49ASU]

Very good hypothesis......I'm a believer.
Thanks.

 

[commonstranger]

Well Brian you did forget one issue...... Ok nevermind maybe you didnt. Laugh Reading that I did answer a question I was asking someone the other day and neither of us knew the answer to it. Thanks

 

[poolkeeper1]

Well after using the par meter, I can say that even the same bulbs brand new bought on the same day do not read the same par value when tested/ 2" from the bulb they differed! so that being said there are many factors that will effect algae growth. Including, light, nutrients, flow, temp,length of photo period and many others I'd guess. Including all the above factors mentioned. Certain algae's prefer certain light spectrums and will thrive under the right combination of parameters. The idea that we can grow only the algae that we want may be a never ending battle, that might be won or might not!