Madcow, whats the gelatin for?
I believe the theory is that you use a gelatine and sugar mix (jelly) in place of just normal granulated sugar, then add your warm water and yeast to the bottle. The jelly mix slows down the yeasts accesss to the sugar and in theory makes your diy Co2 mix last much longer between having to change the mix.
I saw a similar gelatin mix online somewhere and gave it a try once. It did seem to work, but what I saw was a much slower release of CO2 into the tank over a period of about 21 days. This gave lower CO2 levels in my tank. 2 x 2ltr bottles may have given me a CO2 reading closer to the 2 x nutrafin canisters I used on that tank, so I only tried that method once.
Madcow seems to have found that
The sugar yeast method lasts about 2 weeks...
this lasts about 4-5 weeks for most people
My normal yeast gives a good steady output for about a week, it lasts longer, but output drops drastically and the gelatin method gave a steady output for 3 weeks rather than 4-5 .... but I'm sure it all depends on your mix, ambient temperature and tank size.
Also once the mix is used up, you need to throw the bottle away as it is filled with
after the yeast eats/digests the jelly
Changing a sugar/yeast mix once per week takes 5 mins, where as with the gelatin mix you need to make the bottles up in advance to let it set. Obviously as you need to make the mix up at least a day in advance, you couldn't really do this in a nutrafin canister .... unless you had spares !
For me it turned out to be more work for less CO2, but it did last a longer period of time than my normal mix.
Holiday Tip :
However if I was still using DIY CO2 I would certainly connect up 2 gelatin mix bottles into a tank to cover holiday periods if I was going to be away for over a week !
Al
