well yesterday i decided to try inject co2 into my tank but some reason i have failed. Alot of my neon tetras have died and the water was really really clowdy this morning.
and it seems alot of the fish were out of breath
i used a 1 litre bottle siliconed the tubing and then added a air stone on the end of it
what did i do wrong?

Did the yeast mix get into the tank?

im not sure i have a checkvalve
i just looked at it and its filled with a bit of cloudy water
wat do i do now?
i did a water change but its still cloudy

heres a link that may help ............
https://www.plantedtank.net/forums/sh...light=co2+leak

Well the check valve will only prevent water from the tank from getting into the yeast. Check valves only work one way.

It really sounds like your mixture got into the tank. You need to do several very large water changes as quickly as possible.