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dhuffer 11-13-2012 08:34 PM

Lighting question
I am wondering if there are any cons to splitting up the 10 hours of lighting. ie I would like my main lights on for say 2 hours in the morning hours and then off during the day when no one is home and back on for the remaining say 8 hours into the evening for a total of 10 hours of main light. Any issues to the fish or plants?

MSG 11-13-2012 09:21 PM

I don't see why that would pose any problem.
I usually have the lights for my tank turn on about 30 minutes after it gets dark outside. So they're on from 5pm to 3am or 4am.

The tanks double as lights in the living room/dining room.

As long as everything is controlled by a timer...... the fish/plants will adjust to the change in a week or two.

ced281 11-13-2012 10:11 PM

I think one can make the argument about fish and plants being on circadian rhythms, so splitting the lighting may not be optimal for the tank. I haven't seen any data to support this however, so it could be just be conjecture. If you think about people and other animals, they get stressed out when you divide up the daylight schedule but in most cases adjust rather quickly. I'm not aware of any long-term studies on humans or other animals about disrupting circadian rhythms.

I used to split my lighting just like you mentioned and I don't think my fish were too happy about it since they seemed pretty stressed overall. If you use CO2 injection, I'd be careful about splitting up your lighting times if your solenoid valve is also on the same time schedule. It takes time for the CO2 levels in your tank to reach steady-state pressure and also for your plants to use up the CO2 in the water. If you don't have enough surface disruption you might accidentally gas your fish in between your morning and evening light cycles.

ngrubich 11-13-2012 10:27 PM

Some plants need a specific lighting schedule in order to reproduce (i.e. need exactly 10 hours of darkness without any exposure to light to trigger flowering in some houseplants). However as far as I am aware, there aren't many, if any at all, aquarium plants that need a specific photoperiod to flower.
It could also mess with certain fish and their spawning if you have some that are sensitive to photoperiod as well. I know that rainbow trout can trigger early spawning if they are exposed to accelerated photoperiods (like in hatcheries), and ultimately decrease their reproductive cycle by 3-6 months.
I would look into the types of plants and fish that you have / want to get and see if they are affected by weird photoperiods before going with it.

dhuffer 11-14-2012 02:07 AM

Thank you
Thank you all for the points of view and information I may just leave it alone cause I know I'd be kind of peeved if someone kept turning lights on an off on me LOL..... :)

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