Labyrinth fish and co2

Fish are fine in a CO2 injected tank so long as the levels stay around 30ppm or lower. Look into drop checkers for this.

Thanks. What I meant was can you be in yellow in your drop checker if you have a labyrinth fish?

^ The better question is, why would you ever need your drop checker yellow?

Yellow is too much co2 or was it too little?

Naw, you don't want Yellow. You can grow plants fine with a lime green. Fish with and without labyrinths are fine with a lime green colour.

Bettafish prefer calm water compare to the high flow we have in our planted tanks. I mean, it can work, I just don't see it very often.

But yeah, don't aim for yellow, lime green is good.

It all depends. If you have a lot of surface agitation and cooler temps you can get away with more co2. Aim for a 1 degree drop in pH from when the gas turns on until it turns off. That should put you around 30 ppm which is safe for most fish. From there if you want more SLOWLY open up the needle valve with small increments and watch the fish and plants carefully.