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Mid Day Ciesta?

Tom

Member
Joined
8 Sep 2007
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2,631
Location
Kawanabe, Kagoshima, Japan 鹿児島県南九州市川辺町
I've always been told that turning the lights off for a short time during the photoperiod will reduce the risk of algae, due to the algae not being able to store nutrients as long as plants.

But... another arguement I've heared is that this way the lighting is more inconsistant, and algae enjoy inconsistancies as plants prefer stability. Also, algae survives over night yes? So why would an hour break stop it?

As long as I can remember my tanks have had the break mid day and I've not noticed a difference either way. What's your opinions?

Tom
 
Yep as George says its not the light or nutrient part that makes this siesta helpful in an algae fight. Its letting poor CO2 build back up again so that the plants get more consistent carbon source. Normally associated with yeast setups rather than pressurised.

Reducing overall lighting can be a limiting factor for algae but of course slows plant growth as well. This is one reason some people use a 'midday burst'. quite the opposite to a siesta where CO2 is not a worry and the higher light plants get a light boost that they need in the middle of the day whilst allowing the overall photoperiod to have reduced lighting.

Andy
 
Clive and I touch on the subect in this thread: http://www.ukaps.org/forum/viewtopic.php?p=4883&highlight=#4883

Like I said there, on my 25L liquid carbon tank a noonday siesta seems to slightly slow plant growth. (although I did cut from 10hours to 9 hours light at the same time, and of course, other factors may have changed too). I also link to the Dupra website where it claims it stops algae.

I've not noticed any reduction in algae either as a result - I've switched from growing GSA to some black and red ones but that could just be the tank maturing.
 
So there's no real point in me having the break on my 40cm with constant pressurised CO2? The only benefit I can see of it now in my situation is that I can have the lights on earlier in the morning and later at night and not have too long a photoperiod.

Also, just thinking of possibilities here, if I'm adding plenty CO2/ferts etc is there a reason I can't have the lights on for 12h plus? If the plants have all they need nutrient-wise, would that increase plant growth or just encourage algae?

Tom
 
If possible it is always better to have a single photoperiod no matter what time of day you have it as this is more natural for the plants.

For example mine is 2pm to midnight (10 hours)

If you watch your plants they will get to a point where they have had enough for the day and start to curl up their leaves slightly. If you were to extend your photoperiod then it doesn't matter what you ad to the tank. The plants will take what they need and then stop for the day and you are then just extending the period that algae can use to use nutrient. We use 8-10 hours as this is all the plants need. In nature where there is 12 hours there are also huge green water rivers but the aesthetics in a natural setting are not a problem as they are for us who want nice clear water.

In a high light tank some plants will have had enough after 4-5 hours.

Cabomba is a good example of this action. Look at the 'leaves' when they are in the dark. They tend to retract them intowards the stem. When the lights come on they slowly start to spread them. Then you will notice later in the day that even though the lights are still on that they will start to retract them again. At this point the plant is saying 'Thank you, but I am full now and I am going to sleep'

Therefore you can extend your photoperiod if you choose but it will be for the benefit of algae not plants and definately not fish.

Remember that most tropical regions are close to the equator which means they get an equal (or as near to) 12 hours of light and dark a day.

In summary 12 hours is the max but 9-10 hours continuous is preferable as this is all the plants need and having a continuous photoperiod is much more natural for the fish.

Andy
 
Thanks for that explanation. I did wonder if there was a limit to what the plants could take. At the moment my light is on from 8-12 and 3-9, as that's when I'm around the most to look at it. If they'd prefer one block of light, I will change it to 9 or 10 hours solid once I go back down to college as I'm not going to be around to look at it, and I'll see if it makes a difference.

Cheers, Tom
 
I got around this problem by having a 'dawn and dusk' light over my 40g. It's just a tiny pygmy incandescent lightbulb that comes on before the main lights and goes off after they come on. I had it to come on at 7.45 and then go off after a couple of hours when the main light start to come on. It then comes on for about 15 minutes after the main lights go off at night to do 'dusk'. It's light enough to see the fish and feed them ok before I go to school.
 
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