Fiji diy sump baffle kit question (20 gallon)

[CringeTankDaddy]

I bought the Fiji DIY baffle kit and am looking to seal it but when I place it in there is major gaps between the baffle and the side of the tank. I have double checked a dozen times that I have a brand new 20 gallon long. And a kit that matches for 20 gallon long. Is it supposed to be a half inch gap for massive amounts of sealant or is something wrong? I'm guesstimating half inch but it definitely feels like a good distance from the sides.

 

[WhatCouldGoWrong71]

Following

 

[SantiFL]

Old post but any update?

 

[nextevolution3]

i can send picture of my 20 long sump setup using that baffle kit,
i just used painted tape and filled in gaps worked out good