i think many people do something similar. if it were me id get a big rubbermaid type of trash can, and a simple sump pump. drain tank water into trash can, sump pump kicks on and pumps water out to where ever your hose goes.
normal, all woods have sap in it (sap is basically sugar) so its a bacterial bloom eating that. can take from a week to a few months , but it will go away.
its not best for them as mentioned they have a slime coat that helps prevent infections etc. now having said that years ago i had a gar that always refused to get out of the way when i was cleaning and id have to grab him and move him, but i didnt go out of my way to do it.