HCA: Hermit Crab Association

You could do the DIY version: http://hermitcrabassociation.com/phpBB/ ... 39&t=26260 or buy one. You can then set it on a timer, like this one: https://www.amazon.com/dp/B01G6O28NA?psc=1 , to go off at the intervals you want.

I've been thinking about getting one of those. I love your tank. A question though, how tall is the horizontal door?

Wal-Mart sells bags of shells like http://images.prod.meredith.com/product/ca29981797804fc85679b6f60d3b2759/ee785f4e07f0d93ac40d8ed42c3372c6b5e01944982b5b124017a0b0ed3968bb/l/us-shell-large-world-sea-shell-mix-in-a-vinyl-bag for about $9.95. I've always been able to find 6 or so usable shells in the...