Why does the sand have algae?

The biological clock run by proteins, called "circadian" rhythm, shuts down photosynthesis after ca. 12 hours (may vary with the plant). I thought I "knew" that cyanobacteria doesn't have a circadian clock... that it just keeps going and going.

But I just checked with a www.google.com search "circadian rhythm algae photosynthesis" and found that cyanobacteria, algae, dinoflagellates, plants-- all shut down after about 12 hours. Cyanobacteria shut down oxygen production and switch to nitrogen fixing (which is suppressed by oxygen).

So my usual response about "circadian rhythm" is all up in the air...

Carry on, then, while I pull my wits together...

Long hours of light do encourage algae though...

Other, "true" algae I'm less sure about. But after eight or nine hours of light, you're no longer really helping plants.
 
Hey Wetman,

I still can't get on your website man, I'm completely bummed about it.

I have temporarily beaten back my blue green blob with a nearly 3 day blackout. I had to stop because my wife said I was being 'cruel' to the fish.

I have started bringing nitrates up, I had 0 nitrAtes for about 3-4 weeks and I'm thinking about diy co2 for my 20gal cory tank. Do I need to add potasium too?

I intend to add some plants, any suggestions for fairly low light plants? 30 watts I think?

Thanks,

:)
 
Ok, I changed the timer so the light goes on at 10:00 and turns off at 9:00. Quite a bit of difference from my old 6:30- 10:30 setting.

Anacharis, java ferns, and mondo grass do reasonably well in low light.
 
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Ok, thanks for the great tip wetman, now, after a few days of the lights being on for less time, I can see a huge difference. There is barely any algae on the sand if any now.
 
NJDevilsFan,
I didn't know you kept the lights on your tank "on" that long....

My guess is 10 hours is max.. ..and maybe pushing it..

Glad you fixed it. :cool:
 
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