I think I can help with your issue! But, I am not that great explaining concepts so if this does not make sense, let me know?
OK, suction from any source is a certain amt of pressure (psi). Pull force is directly related to it's surface area.
For example, if we have x amt of pull going through x amount of area, we get x amount of PSI.
Lets say we have a filter that is able to pull 2o gallons of water an hour through it's pumpage through an opening of 2 inches. That force of pull is strong. If we can make the opening 4 inches, we decreased the pull by half! If we can make the opening 8 inches, we make the force even less.
So, what I do when I have a certain pull I want to decrease, I make that surface area larger using needlepoint mesh, or bridal view or something. My dwarf tank has an opening about 3/4 inch diameter to a bulkhead drain. I have enclosed it with a needlepoint mesh tube that my fry can actually hitch on and snick snacks as they go by.
Long post to explain a simple concept, but it was something I didn't know until reefer explained it to me. Maybe some one here can use it! Sounds like you have your issue worked out, but if you stay in the hobby long enough, it will come in handy, maybe?