# Lights and co2 auto timer question



## Steve001 (Feb 26, 2011)

alphabeatsco said:


> lights was recommended to be 8 hrs a day across the web, but do you leave it on the whole duration? or split it up partially?
> eg. 3hr ON then 2 hr OFF
> 3hr ON then 2 hr OFF
> 2hr ON
> ...


Lighting levels can and do fluctuate in nature but there's no scientifically valid reason to use that lighting scheme nor is there a naturally valid reason. Observe nature.

As for co2 it doesn't matter if you *run co2 24/7 or if you start it just before the the lights come on and stopped it a short time before the lights go off. In nature co2 is provided constantly. 

* I have no data to back this up it an supposition only. 
If co2 is run 24/7 you do so at a slow rate, slower perhaps than would be necessary when running it in an on off schedule.

Too reiterate; observe nature.


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## Sierra255 (Sep 13, 2007)

From what I've read, there's no benefit or harm done by splitting up the time the lights are on. Many do it so they can see their tank lit in the morning when they leave and again in the evening when they get home. It just helps to extend the viewing time. 

For CO2, many people start it about an hour before the lights come one, then shut it off about an hour before the lights are set to turn off. With the heavily planted tanks some people have, it takes a lot of CO2. If it weren't turned off at night, they would run the risk of killing their fish since the uptake of CO2 by the plants is lessened.


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## Steve001 (Feb 26, 2011)

Sierra255 said:


> From what I've read, there's no benefit or harm done by splitting up the time the lights are on. Many do it so they can see their tank lit in the morning when they leave and again in the evening when they get home. It just helps to extend the viewing time.


Like I said there's no scientifically, nature valid reason. No studies to my knowledge have been done to demonstrate what affect an intermittent photo period has. I agree people do it for their own convenience. It might better to start the light later in the day.



> For CO2, many people start it about an hour before the lights come one, then shut it off about an hour before the lights are set to turn off. With the heavily planted tanks some people have, it takes a lot of CO2. If it weren't turned off at night, they would run the risk of killing their fish since the uptake of CO2 by the plants is lessened.


I've been running my co2 24/7 for close to 30 years. I started doing it this way after reading that nature does it this way. It was know as far back as the mid 80's when the book The Optimum Aquarium came out that co2 was continuously issuing from what the authors called _nutrient springs_. I can assure you you won't kill your fish if it's done wisely. Killing fish with too much co2 can be done, but it might be do to the habit of fish keeping persons over stocking.

My suggestion is for you to check your local library for scientific books on aquatic plants or online. 

Of interest I think


> Excerpt:
> 
> 
> > In an early study of Wisconsin lakes, Juday et al.
> ...


P.S. By Plantbrain:


> Also, the springs in Florida also contain rather high PPM's of CO2, same with Bontia springs in Brasil, and San Macros river in TX etc etc........


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