Lighting: Off and On OK or NO?

[mellowvision]

with the heat being as bad as it is, I have been trying to limit the amount of time I have my lights on... but I've also been doing some gardening in the tank etc... and find myself turning the light on for a half hour and then shutting it off, several times during the day, and then leaving it on for a few hours at night when I really want to watch and stare...

is this bad? should I avoid broken light intervals or is it ok to do this as long as I keep it limited to the total time I want the lights on?

[Nolapete]

I'd say it's bad as you're interrupting photosynthesis.

[geofied]

I doubt that it is bad, per se, but your plants will run out of stored up energy after a number of days (4+) and be left wanting. I would think that any photosynthesis is better than none, but algae may like that tiny window of light as well. Still, not a big deal.

During the last few super hot days, I've reduced light a bit by unscrewing one bulb of two above one tank, and turning on only one strip light out of two on another. Didn't really reduce the water temps significantly, so I've scrapped the idea.

[Ajordan]

I remember reading an interesting article about the circadian rhythm of plants. I think this is the article although I don't have time to read it at the moment. It seems plants can adapt to various lighting patterns as long as there is some consistency.

Link to the article (http://http://www.tiem.utk.edu/~gross/bioed/webmodules/circadianrhythm.html)

[Ajordan]

that link has an extra http:// in it

http://www.tiem.utk.edu/~gross/bioed/webmodules/circadianrhythm.html

[geofied]

That article, in a nutshell, shows that plants will adapt after a certain amount of time. That time is dependant upon the variables. But before that adaptation, the plant will continue, for some time, on the 24 hour "rhythm" until the plant can adjust it's biological clock or until another factor forces a change. The example given for the latter was too much carbohydrate buildup in leaves from receiving high light 24hrs a day.

Interesting article, not sure if it provides much in mellow's case. I guess the good news is the plants will likely try to continue their normal rhythym for a time, which eliminates photosynthesis in this case. Probably a nice buildup of CO2 in your tank(s) though as the plants expell what they have left.

[mellowvision]

good timing maybe, my co2 just ran out on that tank, and I started a new jello.. so it probably had little or no outside co2 for 6 hours or so

[Mgamer20o0]

why dont you wait for it to turn on until its cooler. that why your not turning it on and off. wait until noon or later before having the lights turn on.

[mellowvision]

yeah, I have already adjusted my timers, but I was up early today and wanted to do some trimming, had it on and wondered.

[Mgamer20o0]

if its just a one time thing i dont think you have to worry. some people have there lights go off mid day for a hour or two.