Problem with Euro-Reef CS-6-2+ not sucking air.

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I've got a CS6-3 that I think should have the same size pump.
The shaft should come out of the impeller try soaking it overnight in vinegar/water.
I use a 5/32" drill bit to clean the air intake.
I have to clean the calcium deposits out of the air intake fairly often and the drill is a lot faster than soaking it.