The main problem I see is that your sand will sink to the bottom and leave only
gravel exposed. when you are using sand and gravel it should be known that
small particasl will always fall to the bottom in a mix with larger particals.

Moon
remove nospam from e-mail to send to me, I grow trees in aquariums like bonsai.
I breed dwarf crayfish, great for planted community tanks. If you can get me a
shovelnose sturgeon fingerling (Scaphirhynchus platorynchus) no wild caught
please, contact me