i keep all of my turtles in bare bottomed tanks.its alot easier to keep the tank water cleaned this way.obviously softshells affinity for digging precludes this.for them i keep a sweater box bottom 1/2 to 1/3 the length of the tank with an appropriate depth of sand in it.this allows them to burrow & when i want to change the sand its a quick,easy affair.i usually just throw out the soiled sand & add new.
does it look nice & natural?nope.i believe that my turts are healthier because no gunk gets to buil up in the substrate though.