tonight I was adjusting a dwarf chain sword. It has a runner with 3 clumps of leaves, with roots under each clump. So proud of how the plants are doing in this tank. This morning I noticed the runner’s roots were no longer in the substrate, figured a Cory had gotten under it and pulled the roots out. As I was replanting the roots of all three clumps, I pressed down on the substrate. Boom, large bubbles emerged. I touched about 2” away more bubbles. I ended up pressing the entire bottom and got 15-20 bubbles, some large. I’ve read about anaerobic events with some type of sulfur gas getting caught beneath the substrate and when it releases, it kills the fish. I did smell a little sulfur type smell, kinda like Prime but less so. So it’s 2 hours later and lights out but the fish look normal. My initial thought was to move them to a couple of tanks that have room. Am I past the scare? Guaranteed i’ll Be pressing the substrate on that tank regularly. Edit: the substrate is organic potting mix capped with BDBS. And the tank is only about 5 weeks old.