Questions about flow

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For a CL you need inlets from the tank below the water line either sides or bottom.

My understanding the 2 Little Giants are feed from your sump, so increasing their size, your pulling more water through your sump. Some concerns there; increased noise from overflows, splashing/bubbling where the water enters sump (some of this can be eliminated if having a Herbie), solving microbubbles back into the display.