# CO2 Killed my fish....?



## Consigliere (Mar 21, 2009)

The pH drop may have been the issue, but after 3 days I'm not sure. I would think the first or second night would've toasted them if it was the CO2. Anything else changing in the tank, ferts etc? A change of 6.8 to 6.1 is not really that much.

A lot of folks with low tech DIY CO2 setups do run air stones when lights are off though. I don't but I don't drive CO2 on DIY setups too much.


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## Green024 (Sep 19, 2009)

I may be wrong, but plants take in Co2 when your lights are on, and not when they are off. Turning off your Co2 or diverting the Co2 to outside your tank during your tanks dark periods may be beneficial. I am a noob to planted tanks, but i think i recall reading that somewhere on here.


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## MrThree (Sep 29, 2009)

Thanks guys, No other changes I can think of at all. No ferts or temp swings etc. I am going to try the air stone at night. I 'll let you know if that helps balance the ph... fingers crossed.


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## dewalltheway (Jan 19, 2005)

I ran a DIY system my 55 gal and never ran an airstone at night. How many bottles are you running on your 20 gal? I would run 1 bottle with the line running to a Rex Style Reactor on that setup and let it run 24 hours in the tank with no airstone and your fish should be fine. I ran 2 bottles on my 55 and here are my results with no fish deaths...


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## MrThree (Sep 29, 2009)

Wow that tank is super nice. 
I was just running one 1L bottle.
Someone I talked to mentioned stablizer of some kind, maybe baking soda...?

Right now I have a 1L water bottle.
I added about 1 cup of sugar, about 1 1/2 tsp of yeast and filled 3/4 w/ warm water. 
then line to this glass difusser. 









It was pumping pretty good but now I feel like I am missing something.


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## SamH (Jul 17, 2009)

I'm running a 1.125L bottle with 2 cups of sugar, 1 tsp of yeast and the rest warm water going straight into the outlet of my internal filter. The photo period is around 8 hours and the plants are doing great, did its first trim today. Obvious signs of photosynthesis from the plants (heaps of O2 bubbles) and the fish show no signs of stress. 

60 bubbles per hour? Is that just a bubble from standard airline? If so, mine does at least 30 bubbles a minute.


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## MrThree (Sep 29, 2009)

I wrote that twice but I meant 60 per Min. 
Thats not from an actual bubble counter though....so I dont know how accurate that is.
That diffuser has a piece of glass that allows a bubble up when pressure builds up. 
I just mixed a new bottle w/ about that same recipe you posted + a little baking soda. I think I just had a bunch too much yeast because that thing was pumping it out I just didnt think I could really over due it with a DIY system like that...... 

Thanks for the input everybody....I'll let you know how the toned down mix works.


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