i build this before, the open screen was above water 1" and the hermit crap still get in --> since the opening drain is small, a lot of algae grown there, got to clean it all the time

my other mistake, i added the siphon valve, this failed once in a while (have to keep siphon pump run all the time) or Don't add siphon valve

flood the floor a few times for me with these 2 mistakes.