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what changes in the recipe can I make to increase the BPM/bps of my diy co2? The yeast amount or both the yeast and sugar?

Currently it is about only .5 bps on average. I added 1 cup sugar, 1/8 tbspoon yeast and 1/4 tbspoon baking powder. Does the quantity of water matter?
 

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Assuming room temperature remains stable, the amount of yeast determines how fast the sugar gets converted to CO2, or your BPM/BPS.

This graph, although it actually represents something entirely different (electronic musicians will recognize it), does a pretty good job of showing the production rate over time:



The DIY bottle enters the "release" phase when one of two things happens:

1) Sugar starts to run out.
2) The byproduct of fermentation, alcohol, starts reaching toxic levels for yeast.

Whichever comes first.

Adding more sugar extends the "sustain" phase and overall production time. But if you add too much, alcohol will cause it to enter the "release" phase before all the sugar is used, and the rest goes wasted. You can detect this by tasting the contents of the bottle when production sharply drops off, if it's still very sweet, you have too much sugar.

If the production time was otherwise acceptable, just reduce the amount of sugar, so that less is wasted. Or if you need more production time, add more water - this dilutes the alcohol and delays toxicity.

How much BPS (and therefore yeast) you actually need for your 10G high light tank depends on two things:

1) How the CO2 is dissolved in the water (methods vary in efficiency).
2) How fast it's being lost from the water due to surface agitation from filters/powerheads.

Neither of which you specified. Even if you had, there is still some guesswork involved, and that's where a drop checker that can measure the actual CO2 level in the water comes in very handy.

Assuming you have a HOB filter, I'd recommend starting with this recipe:

* 1.5 cups sugar
* 1/2 tsp. yeast
* 2L bottle filled with water, up to the point where the bottle starts to taper off

Your current 1/8 tsp. of yeast is certainly way too small. In fact, you probably need more than the 1/2 tsp. I recommended. But better to go slow than risk gassing fish. Keep an eye on them when the recipe starts producing and make sure they aren't stressed. If after a day you think they can tolerate more, you can always dump out the bottle and try again, adding 1/4 tsp. more yeast each time. Yeast and sugar are cheaper than fish. ;)

Finally, the baking soda you added is kind of a fine adjustment, which can either help or hinder both stability and production time slightly, and it's not critical you add it for now.
 

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I get pretty solid output from 3 2 liter bottles on a 40 gallon. My recipe is 2 cups sugar, 1/4tsp of yeast. I change out one bottle per week so each one runs for 3 weeks and are still visibly bubbling at the time I change.

I would be more concerned with how well it is diffusing into the water than how many bubbles you are seeing. You can have 3bps and poor diffusion and still not have good results.
 

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Assuming room temperature remains stable, the amount of yeast determines how fast the sugar gets converted to CO2, or your BPM/BPS.

This graph, although it actually represents something entirely different (electronic musicians will recognize it), does a pretty good job of showing the production rate over time:

Funny because though the graph make sense to me now, I would have never understood without being a musician using virtual instruments.

That said, 2 bottles time correctly will overlap in the attack and release stage, giving you a longer sustain time. One bottle works but 2 work way better. It's easier to figure out this chart with one bottle and once you understand, then you can apply it to 2 or more bottles. The "attack" and "decay" are largely unimportant, unless it exceeds 30ppm. The sustain time is important and when you use 2 or more bottles, it's easier to "layer" the "release" and "attack" to where it's less problematic.
 

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what changes in the recipe can I make to increase the BPM/bps of my diy co2? The yeast amount or both the yeast and sugar?

Currently it is about only .5 bps on average. I added 1 cup sugar, 1/8 tbspoon yeast and 1/4 tbspoon baking powder. Does the quantity of water matter?
If you want to boost CO2 production, adding a second bottle in line would be the way to go. 3 would be better allowing you to change 1 bottle out weekly while keeping your CO2 levels more stable.
 
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