My substrate "bubbles" occasionally as trapped gas is released, but usually it's in pretty big bubbles.
Plants that are "pearling" will usually show little beads of oxygen on the leaves/stems. There is also "streaming" which usually is oxygen being released from some damaged tissue in the stem.
It seems like i have trapped gas in the substrate because bubbles are big. There are small ones as well though. But how does gas appear in substrate to begin with? It should still be photosynthesis because i only get big (& small) bubbles near plants. My entire tank isnt planted yet. Hoping hairgrass will carpet.