# Effects of light on DIY CO2



## Feyde (Mar 11, 2009)

I have been using the Nyberg recipe happily for quite some time now and have 2 liter bottles feeding 4 of my tanks. I use 2 2 liters per tank and stagger the refills to try and maintain as constant a flow of CO2 as possible. I even write the dates on the bottles to help myself remember when to refill. I still forget every now and then and the CO2 stops.

As I changed a bottle out on my 20 gallon tonight, I noticed that they only last about 10 days- 14 at the max. I checked the dates on the CO2 bottles for my 29 gallon and found that i would often go 3-4 weeks between changes. In fact, it is bubbling steadily and the oldest bottle was changed on 2/20. The other on 2/28.

I use the same recipe for every refill. The only difference being that the bottles for my 29 are in the dark under the tank cabinet, while the bottles for the 20 are sitting in the open getting lots of light.

All this preamble leads up to my question. What effect does light have on yeast fermentation? Any thoughts from the knowledgeable peoples out there?


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## Seattle_Aquarist (Mar 7, 2008)

Hi Feyde,

You pose an interesting question but what about other parameters such as temperature? Is there other equipment in the cabinet that would make it warmer or cooler than the other location?


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## Feyde (Mar 11, 2009)

Temperature should be the same. Recipe used on all bottles is the same. The only difference is one set of bottles is inside a dark cabinet, with nothing besides a power strip. The other set of bottles is on a table 5 feet away getting ambient light.


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## Big_Fish (Mar 10, 2010)

the only thing I've been able to come up with is a 10 year old science fair project... 
that being said, the material is well written. the young lad followed the scientific method  .... it seems UV light CAN have a detrimental effect on yeast's ability to produce C02 ......

http://www.all-science-fair-project...109/924/827e16299e1cb9aa1d866b68376ff706.html

I'd have to say try covering the exposed bottles... kudo's to the science fair kid if he's right.


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## huaidan (Mar 6, 2010)

Any recipe calling for yeast I've ever heard usually states "put in a warm, dark place" (in the case of bread) or "put in a cool, dark place" (in the case of alcohol).

Yeast are fungi. Fungi usually seem to grow in dark, moist places.

Just some observations.


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