Finally I did it! I placed a small rock under the sand, and placed my squamosa over it. He first didnt like it, and moved away from it, after replacing him on the top of the rock part like 7 times, he finally settled his foot down on to the rock, and pretty rock solid too. Now I wont have a problem when he outgrows the tank, or want to move him to differnt location. Just gotta pick up the rock, and ta dah.