Hey Neven, just a quick question "If i leave my jello CO2 in, and have a airstone or powerhead running when lights are off, is it okay?"
Thanks Neven!!
If you are bordering a solid yellow with no hint of green, then yes for sure. If you are using that much yeast though, you'll likely burn through your jello quicker (still longer than standard yeast water) and be in need of yeast top ups.
As for an update on my Jello Co2. I've only just started noticing a slight decrease in co2 levels. The change is so gradual though that its hardly noticed until you think back to what it was. So sitting at solid green i figured i'd try to top off the yeast again before hitting 20 ppm. I drained the water so only 1/4 of it remained, i mixed 3/4 tsp champagne yeast with 1 cup of 40C water and a pinch of sugar, let it rehydrate for 15 minutes then poured it in.
Result wasn't simply more co2, it was still misting out of my filter outtake despite being broken up by the impeller, so before i killed any fish i opened it up and tossed 1 more cup of water in with a dash of baking soda. It worked in slowing it down nicely

Probably the reason it went insane was now the jello loosened off the bottom allowing for more surface area to the sugars and protiens.
So far it seems to be working great for my tank, i don't get fluctuation of co2 like i was getting when i had the basic yeast water sugar formula, the hardness of the tank keeps the PH swings to negligible. I think i'll fine tune my mix more next time to make it last longer and have less of a burst at the start, and i think the key to that is 1/2 cup less sugar in the jello and perhaps 1/4 tsp less yeast.
Also i'll like to make mention of a member's plight when he gave jello a test run as i did. Eternity302's Tank was practically destroyed by chunks of jello spewing into his tank. He lost fish and many plants, he was forced to do a restart to the whole tank. Its a slap in the face to any hobbyist when they lose their beloved project.
Im mentioning this in this thread, despite it having its own thread, because it is a risk you take whenever you try these methods with your tank. It doesn't need to be jello, heck it doesn't even need to be diy co2. People have ruined many tanks with whatever method thats used. Accident's do happen, but more often its carelessness that'll do it.
so i'll say this for your diy method no matter the type.
SECURE IT! they are very prone to tipping if you use 2L bottles.
Do Not Shake the Bottle while it's connected to the tank. If you do shake it, take the airline off of it.
NO airstones. they are meant for higher pressures so when you connect it to diy, you get 1 of two things, enough pressure to push a larger bubbles out (never misting), or BOOM yeast, sugar water everywhere.
Do not Block the line. Some use a chopstick, just like above, can lead to ruptures of the thank.
DO NOT SEAL IT! you are using DiY, there will be loss, accept it, because sealing wont give you much more life, and most who do seal also disobey the above two 'rules'
Start small! Undersize your first batch just barely, then adjust SLOWLY. Don't go hmmm 1/4 tsp yeast wasn't good enough im goin 1 tsp next. baby steps, you want to perfect the method you use without killing things.