# Photoperiod?



## jschall (Apr 13, 2009)

I have 30w of CFL over a standard 10 gallon tank. I'm growing lots of stem plants: Ludwigia repens and Hygrophila difformis and an unidentified smaller stem. Just redid the tank with ADA substrate. I haven't received my dry ferts yet so I'm not dosing NPK yet, just some tetra brand K+iron liquid I had left over and seachem flourish.

An LFS employee recommended: 5 hours on, 2 hours off, 5 hours on, 12 hours off, saying the 2 hour break would help to prevent algae.
I haven't seen that recommended anywhere else so if anyone could _shed some light_ on the subject it would be appreciated.


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## barbarossa4122 (Dec 31, 2009)

I don't know if this will prevent algae but, I have the lights on from 6am-12pm and 2pm-6pm. I just wanted to give it a 2hr rest. Got rid of algae about 2, 3 months ago using Excel and increasing my Fleet dosing(po4). I am not 100% but, I think this is what did it.


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## ObiQuiet (Oct 9, 2009)

This thread explains some of the chemistry behind the "siesta" photoperiod:

http://www.aquaticplantcentral.com/forumapc/el-natural/67271-lighting-siesta-co2.html


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## jschall (Apr 13, 2009)

ObiQuiet said:


> This thread explains some of the chemistry behind the "siesta" photoperiod:
> 
> http://www.aquaticplantcentral.com/forumapc/el-natural/67271-lighting-siesta-co2.html


Ah, so no go for co2 injected tanks.


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## Tuiflies (Jan 21, 2010)

It still works for injected tanks. I use the siesta mostly so the tanks are lighted when I'm home to see them but it also reduces/breaks up the lights off period. My tanks are lighted for 7 hours so instead of being on for 7 and off for 17, they're on for 3.5, off for 4, on for 3.5 then off for 13. This way the CO2 is only building up for 13 hours overnight versus 17 and it has a chance to build back up before the second photoperiod. Thus my plants spend more time at the higher levels of CO2 when they need it and less is wasted overnight. I'm using DIY, but if you're using press. and turn your CO2 off when the lights are off, then the only benefit would be to build the levels back up if you left it on during the siesta.


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## loj04 (Aug 17, 2003)

Tuiflies said:


> It still works for injected tanks. I use the siesta mostly so the tanks are lighted when I'm home to see them but it also reduces/breaks up the lights off period. My tanks are lighted for 7 hours so instead of being on for 7 and off for 17, they're on for 3.5, off for 4, on for 3.5 then off for 13. This way the CO2 is only building up for 13 hours overnight versus 17 and it has a chance to build back up before the second photoperiod. Thus my plants spend more time at the higher levels of CO2 when they need it and less is wasted overnight. I'm using DIY, but if you're using press. and turn your CO2 off when the lights are off, then the only benefit would be to build the levels back up if you left it on during the siesta.


I could imagine that other nutrients in the plant tissues (NPK & micros) would generate a similar graph as the http://www.aquaticplantcentral.com/forumapc/el-natural/67271-lighting-siesta-co2.html, so it still could be potentially useful.


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## jschall (Apr 13, 2009)

loj04 said:


> I could imagine that other nutrients in the plant tissues (NPK & micros) would generate a similar graph as the http://www.aquaticplantcentral.com/forumapc/el-natural/67271-lighting-siesta-co2.html, so it still could be potentially useful.


Except those aren't really being consistently added to the tank.


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