Join Date: Mar 2004
Location: London, Ontario, Canada
Sorry, my camera won't resolve these extremely tiny bubbles. However, upon further obsessive observation, I see that these bubbles are actually forming on the upper surface of the gravel, not down inside the substrate as one would expect from hydrogen sulfide. Also, they seem to only start after the artificial light has been on for several hours. They start off looking like very tiny steel balls, grow very slowly, and eventually release from the gravel surface and float to the top. I am thinking these are gases being given off by algae. The bowl smells like fresh dirt, not rotten eggs. The plants, snails, and copepods seem to be doing fine.