The substrate was about 8-10 inches deep & had been created from a mixture of eco-earth, oak leaf mulch, semi-rotting oak & birch wood & some old beech nuts. We had taken care not to include any components from pine trees as these can have natural insecticides in them.
We were very confused about the deaths … until we cleaned out their tank.
As we removed layers of substrate the amount of water gradually increased until about a half-inch layer at the bottom was found to be quite soggy. Most telling were the whiffs of marsh gas (hydrogen sulphide or bad egg gas), presumably generated from the combination of sodden soil & the organic matter that it contained.
Hydrogen Sulphide is more toxic than cyanide. So, was there a chance that small amounts of hydrogen sulphide, generated by the decomposition of organic matter has diffused through the soil to kill the millipedes?
Has anyone experienced anything similar?
Until next time …