FishProfiles.com Message Forums

i made my small tank a CO2 rig in a 1.5L soda bottle.
it worked splendidly for two weeks.
one day i came home, found the yeasts "drank" water from the tank, the sealing was leaking, and the bottle sat in a small pool of stinking water.
i cleaned it all up and resealed the bottle, but nothing happens. it seems like the yeast are dead.

how all of this could happen?

it certainly didn't cool down enough to suck that much water in.

Your CO2 bottle should be above the tank, this way it can't reverse syphon.

---

Critical Fertilator: The Micromanager of Macronutrients

A check valve can be used in conjunction with keeping the CO2 bottle underneath the tank. This would prevent a reverse flow of tank water into the bottle.

I've attempted a DIY system prior to getting my commercial system (BioPlast Profistar + 5lb CO2 canister), and my main problem was getting it all sealed up so that I didn't loose pressure. That, and it was really easy to cause a reverse flow by squeezing the bottle too hard... I'm really clumsy, and that happened a few times.

the reverse flow was not a regular phenomena without messing with the bottle. also, i've got a long pipe and hanged it high enough to prevent it.
the bottle is properly sealed. if it wasn't so, i would certainly smell it.

what killed my yeast, and how to prevent it?

the co2 mixture dies around 2 weeks old so you have to make a new one every time it dies out.

what kills it so early, and how to prolong it?

What kills the yeast? I don't know. How to prolong it? You can add baking soda in it. Some people have been able to have their DIY co2 last for a month.

Yeast just dies. If you over kneed bread you use up all the yeast and it won't rise in the oven.
Temperature also kills it, the "little yeastie beasties" as I grew up hearing them refered to can't handle too high of a temp, it could be possible that the room temp reached a high enough point that they weren't happy.
Not all that helpful I know, but all I had to offer.

^_^

What finally kills the yeast off is the concentration of the alchohol they produce. It might be ethanol, I'm not sure. The "yeastie beasties" eat the sugar you put in for them and produce CO2 and alchohol, just like we produce....well....#1 and #2. Baking soda has nothing to do with this, it is generally used to keep the pH from dropping.

---

Critical Fertilator: The Micromanager of Macronutrients

As already stated you should put a check valve in to ensure that the water doesn't go from the tank to the CO2 bottle. These are inexpensive and used to protect air pumps from the same problem.

i liked the extra bottle idea mentioned in another thread better.
temperature is a non-issue. i don't live in an oven or in a sun-bathed tin shack. temp didn't go over 35C, and yeast can survive such heat.

i guess i'll have to play with yeast-juice recipies to find the best one.

I suggest adding a little molassis, protein powder, and Ammonium Sulfate (if you can find it - yeast nutrient). This is from a recipe by Tarah Nyberg in the latest Journal of the Aquatic Gardeners Association.
Also, if you use the above recipe, fill the bottle only about half full because it will bubble quite wildly.

Another tip, instead of worrying about seals leaking, go to Lowe's or some hardware store and find 1/8" by 1/4" I.D. Hose Barb to MIP ADAPTER which should be less than $2.00 and use that. Drill a hole in the bottle cap slightly smaller than the tip of the hose barb adapter, and shove it through with some force. That will create a tight seal. No aquarium sealant, no mess, easy.

I also would suggest a check valve as stated above.

Personally, I wouldn't mind changing the yeast mixture every week--as long as it worked well for that week. I know the Hagen natural CO2 plant system's premixed packets work very slowly at only one bubble every 10 or so seconds, which is quite a disappointment. After using my own mixture of yeast, sugar, water, and baking soda, I am getting 1 bubble every 2 seconds or so.

how old is the mixture when it yeilds 1/2 bubble/sec?

If you can afford it, go with a pressurized system. I've done the HagenPlantGRO system and was impressed but needed longer, better results.

Eventually I went pressurized, I never have looked back. I am in the process of rigging up my other tanks to my main Co2 Cylinder (15lb).

Gary

how old is the mixture when it yeilds 1/2 bubble/sec?

You can't really know. There are so many factors. It depends on what mixture you use!