# How does one choose a photoperiod?



## vanish (Apr 21, 2014)

How does one choose a photoperiod? I see some folks are running 7 hours a day. Others 9 or even 12. Others do multiple periods in a day. I have read plenty of threads where people are advised to cut their light back to reduce algae, but I don't think I have ever read about someone being advised to increase their photo period.

What is the logic behind picking how long to have your lights on?


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## bsantucci (Sep 30, 2013)

First, based on the plants you want to grow and how you will fertilize/pump co2. In my experience that brought me to high lighting. 

Then I started growing some algae which made me realize I needed to drop the lighting levels. I just toyed slowly until I found the right time period/light intensity.

Took me over a year to get there, so I may not be the best teacher haha. I currently run 2 BML LED lights at 65% intensity for 8 hours. There is a ramp up and down in my schedule so the 65% max period is only about 3 total hours. The rest is slightly lower as it ramps up or down.


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## talontsiawd (Oct 19, 2008)

First, I personally find it easier to run a long photoperiod with lower light levels. So on my low techs, I do 10 unless it is problematic.

Most people want the longest viewing period possible, I would imagine. For me, that is why I choose to split it on my current high tech. I am home a lot and I like being able to look at my tanks in the morning and the evening. It also works well for someone who works a 9-5, it's off when I am busy, on when I am not. 

Going with the longest photoperiod possible, there is a point where it becomes troublesome. For high light, it could be as low as 6 hours or so. I have seen tanks were people do as low as 4 but at that point, I don't really see the point. So, you may start at 6 hours and add an hour each week until you have issues. Or, many start at 8 and it's just too long.

One rule of thumb I was taught is when the plants start closing, they stop using nutrients so it's time for the lights to go out. I tend to agree that this is a good stopping point with high light tanks. However, I have found that if you aren't getting algae in a lower light tank, sometimes going beyond that point can add a fair amount of color. I don't recommend trying it unless you know you can get away with it, so in general, that's sort of the basic stopping point. 

Then you get into things like algae, a good way to get rid of it in the short term is shorting your photo period. As you up it, you may get right back to were you were before so you just keep it short, or shorter. 

Again, this is going off the idea that one would want the longest photo period possible. I don't know many who want a short photo period, just because, although in many cases, it can make sense, it's just not as fun.


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## vanish (Apr 21, 2014)

That's some solid info there talon!


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## roadmaster (Nov 5, 2009)

I start with six hours on new tanks and work up from there.
Less chance of algae this way.
In the past,I have begun with longer photo period which often resulted in algae which I despise and had to cut,trim,yank out plant's/hair while lowering the photo period until algae began to diminish.
With shorter light period I saw less algae and began working slowly up one hour at a time.
Hated jacking with lighting,photoperiod,while at same time battling algae that was self inflicted.
Folks think because they inject CO2 that they must also have high lighting when this is not true at all.
Sure,plant's will grow faster with more light but if CO2 or nutrient's are lacking or lighting is driving the demand past what is available,then algae which needs much less of everything will quickly present itself.
Now you have possible CO2/nutrient shortfall plus uber lighting,= algae and poor plant health to deal with all at once.
Can be nerve racking for folks like me who can't get to the center of tootsie pop without biting into the center. (not much patience).
Much easier to start low light period and work up than reducing the lighting AFTER the horse has left the barn so to speak.


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## klibs (May 1, 2014)

Start low and work your way up. I am totally on board with roadmaster regarding lower light w/ longer periods for viewing. If you make large jumps in light intensity / period lengths you can screw up big time and come home to an algae mess. Having been there it is an awful situation and can be avoided with some patience and testing over time.


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