Thanks for the quick reply!!!

1) I was considering both of these. Thanks for the suggestion
2) I think I understand this but only after you make the change suggested in #1, agreed. As it is today, you would have this problem, agree? (Which makes me more confused on why this was originally setup this way with the slits cut down low.)
3) Great point! Thanks.
4) That was my default thought with the Rio pumps. What pump do you recommend for better reliability?

Sorry about not being clear. The Fluval is a Fluval 3 underwater cannister filter. Not sure if this was permanently installed in the tank or not.