I am a Marine science and biology teacher and I am planning on setting up a touch tank for my classroom. It'll have to be low budget but I want these kids to have something small and cool to see and touch since some of these kids have never and may never see some of these organisms ever again. My plan is to get a 45 inch round plastic baby pool to use for the tank set on a table. I know heaters and filters cannot mount to the plastic pool so I have a small 2.5 gallon tank that i am going to inversely mount all equipment to such as wave maker, hob filter, heater and surface skimmer. I will be able to have sand and live rock in the pool as well. I plan to just have some things such as easy little inverts like urchins, emerald crabs, cleaner shrimp and chocolate chip stars and such. My question is, will these animals crawl out of the tank? What can I do to prevent this? Again, low budget options please, I am just trying to help some inner city kids who haven't seen salt water animals to experience it in person.