This will fly in the face of what some propose but I totally find the idea of sand trapping gas to be somewhat overblown as a hazard. I can see it "might" happen in some extreme cases but then I also find lots of confusion and false info passed around when fish die. It is very much easier for me to believe fish die and we don't know why than it is for me to believe a gas will be trapped by something as porous as sand. I will believe it possible if the sand is really poor grade and left to pack down into a solid sheet but I don't see that being possible if plant roots and snails can move through it. It takes a pretty solid, tough membrane like a balloon to hold gas under water.
I may get caught someday and regret it but I have never had a fish die from trapped gas so I just go along with the normal flow and ignore the hazard. If your tank begins to stink, yes, you do have a problem and the fish may die but I'm guessing most of us have that figured already? No reason to pass gas on the subject!