Over time my troughs have built up a healthy layer of seeding medium, organic sludge and rocks that my daughter likes to deposit along the edges. After close examination I have found that this layer is teeming with life. I have a healthy population of gammarus, midge fly larvae(red worms) and composting worms. There are also many small creatures that I cannot identify. All these creatures are contributing to the ecosystem and have found their niche and balance. Many people ask me how often I clean the troughs and I tell them NEVER. I want all those creatures in the troughs and ecosystem. As long as the material in the bottom of the trough does not smell rotten all is well. I believe this layer can tell you a lot about the health of your system.
So, what is in the bottom of your trough?
Vermiculite and coir mixed with fish poop, a dash of detritus, tetras, algae eaters hiding out in the funk, some small snails clinging to the bottom of the rafts, and gammarus colonizing every root bundle. Thank god for white liner!
With a DO of 6.5 - 7.5 in an average of 75F degree water.