I refilled my diy co2 bottles Monday night and when I came home from work Tuesday, all fish fish were gasping for air. One dead, a few close to death. I put an airstone in and within a half hour, all were back to swimming around.
Question. Do you guys provide aeration overnight to avoid this issue? In the past I've had the co2 running all the time with no airstone and no problems. Or is this just a one off deal?
Should I put an air pump on a timer to provide aeration overnight?
For yeast generators, you want to adjust your mix so that when it runs overnight, your CO2 in the morning is just right (25ppm typically). Then, as the plants use the CO2 during the day, it will likely drop alot, requiring the entire evening to get it back up to 25ppm for lights on again.
I'd say look at your mix. How much yeast and how much sugar are you adding? How are you getting the CO2 into the water? What size tank?
The thing to remember is that plants only consume CO2 when photosynthesis is taking place - and of course that can only take place when the lights are on. In fact, I'm pretty sure that plants can/do actually release excess CO2 at night, which would explain the sudden and almost tragic overload in your tank.
The airstone will keep the CO2 levels lower, but I would be inclined to actually remove the CO2 line from the tank at night if it's not too much hassle.
It is also possible that your newly refilled system just had an output spike, but there is really no way of knowing.
I would have to agree and say that it is a CO2 spike because you probably just re-filled it. I would suggest tapering the measurements of yeast/sugar down or at least reverify them.
What I have done is setup 3 diy CO2 generators i.e. 3 x 2 litre bottles and stagger the setup by a week so that when one is done you have 2 others still generating CO2. This will produce a more consistent CO2 output. I would be reluctant to remove the CO2 line from the tank at night because this may lead to a PH fluctuation that some fish don't handle to well.
My question (uh ummm BigDaddy) Can the CO2 saturation in a tank be effected by running an airstone 24/7? I would think that the air bubbles aren't going to 'kick out' the CO2.
I've been running pressurized CO2 and an airstone in my tanks 24/7 for many months with good plant growth and no fish health problems at all. In fact I refilled my cylinder yesterday and resumed the same guage setting and bubble count when I reconnected it. I should attribute my lack of problems to luck as opposed to skill/knowledge as I've never taken readings of the water since starting the injection.
I do usually stagger the bottles but I was a little tardy and they both were not running for a few days. I hope the sudden rush of co2 was just a temporary spike as you said and once I get back to the regular routine things will stabalize.
I use 2x2 litre bottles with the ladder diffussers. One teaspoon yeast to one cup sugar. Is there a better mix to create more slow but consistent output?
Tank size is 40 gallons.
Way too much yeast for that size tank!
Try 1/4 tsp of yeast and 2 cups of sugar.
Production will be slower, but your bottle should last a lot longer than it has been.
Okay, will do that. Thanks.
One more question. Could I use a four litre bottle as a co2 generator? Would I have to double the yeast sugar ratio to achieve the same results? Or should I just stick to two litre bottles?
Okay that was three questions. :D
Staggering 2 2 litre bottles is safer. It will prevent potential mishaps.
How do you test for CO2?
http://www.qsl.net/w2wdx/aquaria/diyco2.html
Here is a good web page of information on CO2. In it you will find a graph with the relationship between pH and KH and CO2 levels.
You measure your kH and your pH.
Then you check it against this chart:
http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm
Thanks everyone for the help. This forum is cool.
Quote from: "BigDaddy"Way too much yeast for that size tank!
The amount of yeast pitched
does not relate to the rate of CO2 production.
The yeast goes through 4 stages (lag, growth, fermentaion, and sedemtation). When you pitch the yeast (i.e. add it to the sugar solution) it will propagete until a certain level is reached before fermentation (the stage where alcohol & CO2 is produced as a by-product). Just look at all the "sludge" (spent yeast cells) left over in the container when you go to change the solution.
The amount of yeast pitched will have an effect on the time it takes to start CO2 production but will not effect the overall rate.
Since you are basically making beer here is the life cylce of brewers yeast (if you are using bread yeast it also behaves the same as brewers yeast)
Brewers Yeast Life Cycle
The life cycle of yeast is activated from dormancy when it is added (pitched) to the wort. Yeast growth follows four phases, which are somewhat arbitrary because all of the phases may overlap in time: 1) the lag period, 2) the growth phase, 3) the fermentation phase, and 4) the sedimentation phase.
Lag Phase
Reproduction is the first great priority upon pitching, and the yeast will not do anything else until food reserves are built up. This stage is marked by a drop in pH because of the utilization of phosphate and a reduction in oxygen. Glycogen, an intracellular carbohydrate reserve, is essential as an energy source for cell activity since wort sugars are not assimilated early in the lag phase. Stored glycogen is broken down into glucose, which is utilized by the yeast cell for reproduction – the cell's first concern. Low glycogen levels produce abnormal levels of vicinal diketones (especially diacetyl) and result in longer fermentations.
Growth Phase
The growth phase, often referred to as the respiration phase, follows the lag phase once sufficient reserves are built up within the yeast. This phase is evident from the covering of foam on the wort surface due to the liberated carbon dioxide. In this phase, the yeast cells use the oxygen in the wort to oxidize a variety of acid compounds, resulting in a significant drop in pH. In this connection, some yeast strains will result in a much greater fall in pH than others within the same fermenting wort.
Fermentation Phase
The fermentation phase quickly follows the growth phase when the oxygen supply has been depleted. Fermentation is an anaerobic process. In fact, any remaining oxygen in the wort is "scrubbed," i.e. stripped out of solution by the carbon dioxide bubbles produced by the yeast. This phase is characterized by reduction of wort gravity and the production of carbon dioxide, ethanol, and beer flavors. During this time period, yeast is mostly in suspension, allowing itself dispersal and maximum contact with the beer wort to quickly convert fermentables. Most beer yeasts will remain in suspension from 3 to 7 days, after which flocculation and sedimentation will commence.
Sedimentation Phase
The sedimentation phase is the process through which yeast flocculates and settles to the bottom of the fermenter following fermentation. The yeast begins to undergo a process that will preserve its life as it readies itself for dormancy, by producing a substance called glycogen. Glycogen is necessary for cell maintenance during dormancy and, as mentioned, is an energy source during the lag phase of fermentation.
Well now there is conflicting answers here. On one hand, less yeast equals less output but longer time producing.
The second hand says the output will be the same, but the time to co2 production will change.
So it seems to me that more yeast would lead to a faster start and longer production since the output is the same.
Help me. I don't get it.
My guess would be that you would have a sigmoid curve. I.e., increasing the amount of yeast would increase CO2 production to a certain point, after which the max output would be reached, and ur graph would level off. As to what that amount is, I'll leave that to one of the experts.
I also suspect that less yeast would extend the time CO2 is produced for.
What stops production in a DIY setup is the alcohol produced. The yeast can only handle a certain level of alcohol before it dies off.
More yeast equals a quicker build up of alcohol in the generator.
Less yeast means longer production because it takes longer for alcohol levels to kill off the yeast.
At least... that's what I've been told....
Quote from: "BigDaddy"More yeast equals a quicker build up of alcohol in the generator.
Less yeast means longer production because it takes longer for alcohol levels to kill off the yeast.
That makes sense.
Quote from: "BigDaddy"What stops production in a DIY setup is the alcohol produced. The yeast can only handle a certain level of alcohol before it dies off.
That is true. However, the amount of sugar will dictate the amount of alcohol. The yeast will keep munching on the sugar until all the sugar is gone in which case the yeast will go dormant or it dies because of the amount of alcohol (some yeast can handle 15% alc/vol). If all the sugar is consumed you can add more sugar and the yeast will reactivate (FYI. this is how champane is made. The wine is fermented and added to the bottles. Some grape juice is added to the mix and corked. The second fermentation cycle naturally carbontes the wine making champane.)
Quote from: "BigDaddy"More yeast equals a quicker build up of alcohol in the generator
The yeast you start with replicates and then starts to consume the sugars. Just look at the amount of spent yeast you end up with when you clean out your generator. You end up with way more yeast at the end than you start with. The more yeast you start with the faster you get to the fermentation cycle.
Quote from: "BigDaddy"Less yeast means longer production because it takes longer for alcohol levels to kill off the yeast.
Less yeast slows the start of the fermentation cycle. Because life cycel of yeast overlaps it appears that the CO2 is slower but once the yeast reach "critical mass" it is consumed at the same rate.
I'm not sure if you are agreeing with me or not. :lol:
Essentially, we have two volumes of yeast in comparatively the same amount of solution (an almost filled 2 litre bottle).
Solution with volume X of yeast will produce less alcohol and thus be better able to consume sugars longer than the same solution of 4X, where alcohol concentrations will increase in solution significantly faster.
In other words, I believe the popular opinion is that most of our yeast generators stop production because of alcohol levels, and not from sedimentation.
What I am trying to say is that both will produce an equal volume of CO2.
Solution A starts with volume 1X of yeast. Solution B starts with 4X yeast. Solution B starts to ferment and produce CO2 instantly (*not realisitic just used for demonstration). While solution A does not produce CO2 until the yeast has multiplied to the 4X level at wich point solution A starts to produce CO2 at the same rate as B. Frome now on A and B consume the fermetable sugars at the same rate. So, solution B will "last" longer only because it started producing CO2 later. The same volume of CO2 will be produced by both.
I just mixed up a batch using 1.5 Liters water and 1 cup sugar and got a specific gravity reading of ~1.064 which equates to ~8.5% alcohol at 100% fermentation. Table sugar is not very fermentable and it is probable that all the fermenatable sugars get used up before the yeast dies (at this concentration).
Why wouldn't solution 4x have to go through the same lag and growth phase as 1x?
Additionally, while the total volume of CO2 dispersed would be the same, is it not a time release issue? Volume 1x generates a CO2 rate more manageable to the aquarist, while volume 4x, as you have pointed out, starts fermenting much sooner (and therefore providing too much CO2 out of the gate).
Solution 4x has to go through some growth as well (that's why I put the disclaimer of not realistic) just not as much growth because it started with a larger pitching rate.
Ignoring the lag phase, lets concentrate on the growth phase:
II) The second phase is the accelerating growth phase during which yeast cells start to grow and divide. Signs of fermentation will also become apparent. The yeast begin storing sugar in the form of glycogen for later use.
III) The third phase is the exponential phase where yeast reproduction and metabolism is in high gear. Cells are dividing every 90 - 180 minutes and fermentation begins. During this time the number of yeast cells may increase as much as 1000-fold (or 3.0 logs) within 24 hours. The extent to which the cells divide is dictated primarily by the pitching rate. If appropriate pitching rates are used, the yeast are pitched at high concentrations (5-15 million yeast cells per ml) and undergo approximately 3 generations (23- or an 8-fold increase in cell number) to yield 80-100 million cells per ml. 100 million cells per ml is about the maximal concentration of yeast attainable in fermenting wort [Wort, for those not familiar with brewing beer, is the unfermented sugar solution i.e. the almost the same as what is in the CO2 reactor.]
IV) The fourth phase is the decelerating growth which should occur 12-24 hours after pitching. At this time the oxygen is fully depleted and fermentation and CO2 production is taking over. Fermenting wort should be in high krausen. Heat is being generated and there should be rapid CO2 evolution (bubbling).
So, while solution 1X is still growing (phase 3) solution 4X has reached phase 4 and started to really generate CO2. Since both 1X and 4X reach the same conentration of yeast which are producing the same amount of CO2 there will not be "too much CO2 out of the gate".
And again, I do not argue with the total volume of CO2 being produced, but rather the amounts produced over the total time frame.
There is evidence that yeast mixtures last longer (for our purpose of CO2 production, not for fermentation in general) if you decrease the amount of yeast, and conversely last shorter periods if more yeast is used. Lower yeast also means less CO2 produced per minute, but produce more consistantly over time. Higher yeast levels will cause an initial higher burst of CO2 production with a gradually declining production over time.
So again, I do not argue that the total volume of CO2 produced won't be very close. Rather, since aquarists are concerned with how many bubbles per minute the generator is producing, less is more when it comes to DIY CO2 generators. Less yeast means a slower, but more consistent, bubble per minute rate. More yeast has a significantly higher bubble per minute rate at the outset, which gradually tapers off.
Since our goal is to maintain relatively equal concentrations of CO2 from day to day, a more consistent number of bubbles per minute is more desirable.
My head's starting to hurt :shock:
I agree, my head hurts too. Why not just buy a 10 lb C02 bottle and be done with it?
I agree with both of you ...jabber and BigDaddy. I started with 1 teaspoon full. The bubbles started very quick, and the rate was quiet high and slowing down after. I reduced it by half, and it takes longer to starts producing bubbles. The rate is also slower. I am not an expert, so it took me a few tries with different recipe until I am happy with the result. Good luck Iceman.
PS - I used to be a DIY guy... but I've gone pressurized and I'm not going back!
Quote from: "Nelson"My head's starting to hurt :shock:
And I liked this it! :lol: Reminds me of days when I was in a science...
Quote from: "BigDaddy"PS - I used to be a DIY guy... but I've gone pressurized and I'm not going back!
It's absolutely the only way to go. It's an investment at the outset but it's worth every penny not to be concerned about continually recharging a DIY setup. The conveniece of adjusting for a constant flow is also great.
So how much does it cost to set up a pressurized system for a forty gallon tank?
Pressurized is not tank dependant... a pressurized setup will work just as well on a 10 gallon as it will on a 200 gallon.
If you bought everything brand new (tank, regulator, solenoid, bubble counter) - it'll run you 340 bones from a local store that carries the stuff. Same setup without the solenoid would be 260. If you are lucky, you might be able to find a used CO2 tank, although the guys where I get mine filled say they are getting harder to come by these days for some reason...
Then you also have to look at how you are planning to dissolve the CO2 into the water column (a DIY inline reactor will cost you a few bucks in PVC... commercial products will cost significantly more).
When you say local store, do you mean pet shops?
No... aquaria canada sells co2 equipment. They use CO2 in calcium reactors for saltwater.
You can get the stuff online too.... but I just used aquaria canada's pricing 'cause it was easy to find.