To Much Light?

Axleuk

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Hi Folks,

Just a quicky.

I am aware that you need at least 10 hrs of light in order to maintain good health for live plants in your tank, but does extended use of your light harm the fish in anyway?
 
The fish need to sleep much as we do. If you never give them a dark period it will make their life more difficult. 10 hours a day of light won't hurt most fish.
 
as Oldman says as long as the fish (and plants) get 8 hours of darkness so they can rest, then they will be fine and you can have the lights on for the rest of the time (up to 16 hours per day). Most people have the lights on for about 10-12 hours per day and see how the plants go. If the plants grow well and you don't get much algae, then you can increase the photoperiod a bit. If you get lots of algae then decrease the time the lights are on.
The other thing is the intensity of the light. If you get 400watt metal halides and put them on a tank that has only had fluoros on it, then the fish will probably stress a bit. Under this type of situation it would be better to have the fluoros on for a bit and then turn the halide on for an hour each day. Every week you would increase the time the halides would be on. The fluoros can be turned off when the halides are on.
The other thing is if you turn the tank lights on first thing in the morning while the room is dark, then the fish will stress out a bit and possibly dash about the tank or maybe even jump out. It is best to open the curtains or turn the room lights on 30 minutes before turning the tank lights on. And if you have more than one light on the tank then turn one on, wait 30-60 minutes and then turn the other on.
At night turn the room lights on, then turn the tank lights off. Leave the room lights on for 30 minutes before turning them off. This gives the fish a chance to wake up and go to bed without being subject to sudden bright light or darkness.
 
Thanks guys thats great advice.

One more thing. My tank has two switches. 1 switch has one light, the other switch has 2 lights. Personally i prefer 1 light as it makes the tank look more in contrast if that makes sense, but what is better, brighter light? or is it a matter of personal preference?
 
It depends more on how much light your plants like. If they like to bathed in light, then go for the two and possibly all three all day. And then you use a timer (if there are seperate chords as well) for creating a quasi-sunrise and sunset. Many marine reefers do this to simulate the photoperiod of the whole day for corals as this helps the corals "wake-up" in the morning and being to close up at night. The same will be good for plants so they are just not all of sudden blasted with high intensity light

For an example... the T5 hood I have for my reef is 2 x 10K whites, and 2 x actinics. This is how my lights work through the day:
- 7am - actinics on
- 8am - 10k whites on
- 9am - actinics off (though some leave them on all day for the extra light for some needier corals)
- 5pm - actinics on
- 6pm - 10k whites off
- 7pm - actinics off

My hood also has moonlights so usually I turn them on about this time for a couple hours before I go to bed. This simulates the sunrise/sunset effect by using the different tubes.

Ox :good:
 
Plants don`t need more than ten hours of light a day. If you have any plants more demanding of light, you could give a mid photoperiod burst of two or three hours using all three lamps to cater for their needs. Running all three lamps for extended periods of time could bring you some algae problems.

Dave.
 
Yes, I have algae problems (probably related to carbon problems as addressed in a good post by Dave recently!) and one of the things I've done to try to start dealing with it is to put a timer on each of my two lights and give my tank a siesta without the lights on for 4 hours in the middle of the day. The morning and evening photo periods I can add up to either 8 or 10 hours, haven't settled on one for sure yet.

The timer thing seems like it can't hurt and gives added flexibility.

~~waterdrop~~
 
As long as you are aware that the necessity for a siesta is an indication of poor CO2.

Dave.
 

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