Ran a Liquid Rubber tank for almost 8 years, never put sand or gravel in it,
but suspect that it some of it would imbed itself in the liquid rubber to one degree or another.
Liquid Rubber stayed pliable and slightly sticky even after 8 years underwater.
Dropped various things in tank over the years and had no damages to rubber it was just marked/indented by the bump and then returned to normal condition so it works for protection.
When ever I was putting something heavy in tank or a bunch of decorations of one sort or another.
I put a sheet of plastic on bottom an then sat whatever on that. Went to hardware store and found
in toy section, cheap and various colors
https://www.homehardware.ca/en/54-green-turbo-sheet-sled/p/7471172
Liked the light blue w/dark blue striped ones, just cut with scissors to fit.
Believe what happens with these is that there is still a film of water between bottom of tank and plastic sheet, so I had no stick to bottom issue. But don't know how it would perform with a load of gravel completely covering it.
Also tried putting a sheet of
https://www.homedepot.com/p/Plaskol...-Crate-Light-Ceiling-Panel-1199233A/202025149
down on the plastic sheet and the decorations etc on top of that. This looked very nice, bright, and unique, but not fishscape you appear working towards.
