I would skip the sand altogether. Then you can have one type of snail that'll munch on the glass floor and keep your tank very clean. Keeping your sand clean can be a pain!
Also, if it's your kids tank why not get a clown? Nemo got to be what they want, right? One clown and one cleaner shrimp and you've got a nice stock.
Also, if it's your kids tank why not get a clown? Nemo got to be what they want, right? One clown and one cleaner shrimp and you've got a nice stock.