I have a planted tropical community tank which has a layer of roughly 3cm of fine sand substrate. I've read a lot about anaerobic gas build-up in the substrate where it is not regularly turned over and moved. When I shift the sand I get very small bubbles rising. This has been happening for a while and it doesn't seem to have a negative impact on my tank.
Some of the 'solutions' to this problem, suggested with varying levels of controversy across the internet, include:
- Having a thin layer of substrate
- Using gravel not sand
- Regularly disturbing the sand to stop the build up
- Increasing water changes to handle the toxic nature of the gas
- Get snails to stir up the sand
None of these necessarily seem like a perfect solution. In a planted tank, I rely on having enough substrate to create a stable foundation for the plants. Compost/sand definitely seems to grow them best. Gravel lets us easily stir through it to remove any of detritus that is underneath but doesn't hold plant roots well (at least in my experience). I also have some snails which live in the substrate and I would assume that they help stir the substrate up.
With all this in mind:
What is the best way to prevent anaerobic gas build-up in a planted aquarium, assuming it is in issue?