I snipped a 1/3 of my used Aquaclear sponge and cleaned in in used tank water. The stuck my scissors vertically in the shortest end and snipped 2 times. Then I shoved it over the intake, and tugged until it covered all the holes. I haven't lost a baby shrimp, fry, or CPD since. I had a CPD actually sucked up once, just before lights out. Took 2 people (me and my husband) 10 minutes getting him out. I had the 2 intake extensions connected. He was stuck between the 2. I have no idea how she did it. But no more. She lost an eye, part of her jaw, and little back skin.
Plus its easy to clean, I just dunk in used tank water and squeeze. It catches a lot of junk and serves as additional BB grounds.