# light duration



## mike b (14 Mar 2015)

Hi there. I'm making a return to planted tanks after a long lay off. I've dusted of my needle valve, bubble counte etc and gone and bought a new cylinder. Everything is in place and I'm  turning on the co2 2 hours before lights on and turning it off 2 hours before lights off. I've not had a planted tank using co2 since the mid nineties and I know a lot has changed since then. I've tried to learn as much as possible but I'm still stuck on light duration. Back then all the books seemed to recommend 10-12 hours light (they recommended a lot of nonsense it seems such as cable heaters, mid day siestas etc). Just wondering what is the minimum and maximum light duration I'm looking at?


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## tim (14 Mar 2015)

Hi mike, 5-6 hours for the first few months upto 8 hours maximum works for my high and low tech tanks.


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## mike b (14 Mar 2015)

Thanks Tim for the quick reply. Amazing how advice has changed. I'm not the most technically gifted person and I'm fairly new to the Internet.  Will your light recommendations work for all plants ( red stem, ground covering species)?


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## Andy D (14 Mar 2015)

Yes.


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## ian_m (14 Mar 2015)

Initially start up at say 4 hours possibly reduced light level to let plants bed in and not get algae. Start CO2 2 hours before lights on and off 1 hour before lights off.


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## Andy Thurston (14 Mar 2015)

tim said:


> Hi mike, 5-6 hours for the first few months upto 8 hours maximum works for my high and low tech tanks.





ian_m said:


> Initially start up at say 4 hours possibly reduced light level to let plants bed in and not get algae.


I'm with tim on tis one 5-6hours but with reduced intensity unless co2 technique is seriously crap 


ian_m said:


> Start CO2 2 hours before lights on and off 1 hour before lights off.


2 variables that might need adjusting mine comes on 2.5 hours before lights and goes off 4.5 hours before lights
whatever works best for you in your tank


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## mike b (14 Mar 2015)

Thanks for all the advice. Just wondering though why 8 hours (after a few months) is the maximum time lights should be on? Is this because of algae issues or because plants grow so rapidly that it cuts back of trimming plants?


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## foxfish (14 Mar 2015)

Hi Mike, opinions have changed over the years but it does not necessarily mean ....."recommend 10-12 hours light (they recommended a lot of nonsense it seems such as cable heaters, mid day siestas etc" ..... did not work for us!
I used all those methods and my tanks looked great, the main difference is ... now folk use bright lights!!
I can remember using 12 hours of light but the stem plants would close up their foliage after about 10 hours & I guesse the other two hours were just for my enjoyment!
Now we use different methods, bright light for 7-8 hours works well but if you want to use a longer period you need to use less light.


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## mike b (14 Mar 2015)

So basically the more intense the light, the less the lighting duration? Yea cable heaters worked ok but bit annoying when plants roots tangled round it and you'd end up pulling the cable heater out of the substrate when uprooting plants to trim down lol. Wouldn't have one again


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## foxfish (14 Mar 2015)

Well yes but more to the point is that ... using modern lighting coupled to EI dosing & optimum CO2 only requires 7 hours of photosynthesis  to obtain healthy plants without nuisance algae.
Not to say some folk don't use different methods to obtain the same results but this is a good guide line that works very well for many...


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