to cobra, aqua soil is loaded with organics, it is not inert, nor inorganic
its basically fired dirt IMO.
that being said even if it absorbed the h202, it would break down over time. i think the root cause to melted plants is as some have interpretted.
dead bacteria, = ammonia. too much ammonia can melt a plant
carefully done gravel vac's on aqua soil are OKAY. don't just ram it into the susbrate, but gently wiggle it around, it'll do the job, aquasoil is light and is easily fluffed around by the siphon