thanks verry much .....theres NOTHING worse than a breeding parrot for digging substrate!!!!!!!! i have had hundreds of species over the years but they are far the worst ,they have a clutch of eggs every 2 weeks !!!!!!! so they are constantly preping nests and caves ....sand is much better !!!!!! they cant pile it up and it settles QUICK the current in the tank flattens out the ditches in an hour or 2 !!!!!!!!! and its much cleaner as the waste just rolls allong the surface and into the intake strainers!!!!!!!!!!!