Originally Posted by Monster Fish
Don't be worried. It's just CO2 gas being released from the breaking down of organics in your soil. If you're worried about it, just poke the substrate with a bamboo skewer at different places every day.
I have a dirted tank with sand as a cap that I just set up its into about 10 days now and I don't have that problem with that tank the other one has oil dry as a cap and when the dirt bubbles it comes through and my tank looks like crap dirt floating in the water and on the plants everything is doin fine but that is my only problem?