How Long Do You Keep Your Lights ON?

11 hrs plus sunlight

The tank lights come on at 9 am and stay on until 8 pm.

2 of the 4 tanks get sunlight in the morning for a few hours before 9 am. The tanks are 6 or 8 feet from the window and the light comes in from the side and only hits part of the tank at any one time -- I wouldn't know how to quantify that; short-term intense partially direct lighting? It makes the anubias bloom.
 
Mine have the same schedule, 9 to 8. Well, 2 of the 3 bulbs have that schedule. I still haven't got a timer for the other one so it gets turned on and off when I have a chance so it's usually on 10:30 to about 7. Maybe it helps make it a more natural sunrise-sunset.
 
Same as many - 10 hrs on a timer. They come on around 11am and go off about 9pm. It works great for the plants, but the fish have learned the schedule and if the lights go out before they get fed (I usually feed about 8:30pm), the fish get a bit upset - lots of quick swimming and splashing.
 
10 hours...12:00 pm to 10:00 pm. The tank receives natural room light until noon when the lights come on via a timer. My 80 gallon tank is equipped with 2 seperate lighting systems, 220 watts on a VHO ballast, and a normal 40 watt florescent strip. I'll turn on the 40 watt light late at night if I can't sleep, or if I have a headache which creates a very subdued ambient environment...very peaceful and relaxing.
 
Christel Kasselmann's opinion.

Let me quote the brand-new English version of Christel Kasselmann, Aquarium Plants, 2003, here, just to get her thoughts into our discussion. Aside from her extensive light-meter reading of water plants in their native waters, she gives a section "Light in the Aquarium" --part of which discusses "Daily Lighting Periods" (p. 51f):

"It has previously been concluded" she writes, "that that lighting period in the aquarium has to last only 8-10 hours. This conclusion, however, has to be strenuously contradicted... a middle course, which satisfies just about all plants, is suggested. This compromise consists of a minimum lighting period of 12 hours. The maximum lighting period is less critical and can be around 15 hours."

I've never run my own lights longer than roughly ten or eleven hours. I better rethink this eh!
 
My tanks are all on timers, and the lights come on throughout the day. They all go off before 9:30, since between FW and SW, we can light the house very well just with tanks. The longest period is about 10 hours, the shortest is about 6 hours. The heavily planted, CO2 supplemented, fertilized tank gets 10 hours, with about 2 hours of direct sun and then 4 hours of bright ambient lighting. The newt tank, with only a few small plants, gets 1 hour of direct light and then 6 hours of the bright ambient light. The tank light comes on around 2 and goes off just after 9. The newts are more active with this schedule than anything else.

I've been very happy with my pin timers. They are not at exact as the digital timers, but after having 3 of those die, I've decided I'd never use them again. The indoor-outdoor timers are better, IMO, since the occasional splash of water won't fry them.
 
Light levels vary in time and space, one or several readings might not mean much. But it's a lot of work to monitor a system for light over the course of a year and even then the year to year variations might also play a significant role.

Nature is NOT always optimal or desired when growing plants. Assuming so will get you into trouble. Many places where plants grow have around 40-50% of the growth in the form of algal primary production.

I've seen a general trend over the years reducing the lighting from 12-14 down to 10-12hrs/day.

Some very nice tanks have been produced with 10-11 hrs of light.
Perhpas the intensities will start to drop as well, many folks have too much light for their routines they want to try and it takes them longer generally to hit a nice balance with their tanks with higher light.

2w/gal of PC lighting is a good deal of light vs the old 2w/gal NO FL lights w/o reflector etc.

Intensity and duration both play a role together.
This is perhaps one reason why the day length has shortened also.


Regards,
Tom Barr
 
AquariaCentral.com