Still not sure how to mount the dome to the too of the tank with the screen lid on. But I have a new set of problems

Today I put the substrate in the tank and the filter, not entirely happy with the way everything looks froma. Design standpoint but is is my first try and only needs to please my 3 year old mans 6 year old. And they love it. Anyways on to the problem. The filter isn't working. I mean it powers on and everything but no flow. I opened it and filled it with water. Filled the tank about 3" full and waited. Half hour later nothing coming out of the filter still. Any ideas? My only thoughts are that the water is t able to deep through the weedblocker. Too dense? So I'm thinking of pokin holes in it randomly with a nail. Thoughts?

I haven't taken the filter out to see if there is water on that side if the false bottom but another design flaw was that it's almost impossible to get the filter out :-/ once time for maintenance comes around I'll fight that battle...