An insert for a liquid-holding container may include a body comprising a wall, open first and second ends, and a lumen extending from the open first end to the open second end. The insert also may include a plurality of first openings formed in the wall, the first openings being situated between the first and second ends, and each of the first openings defining an area, and one or more second openings formed in the wall, the one or more second openings being situated between the first and second ends, each of the one or more second openings defining an area that is greater than the area defined by any of the first openings, where at least one of the one or more second openings is situated closer to the first end than any of the first openings, and wherein each of the first and second openings is sized to permit the passage of a liquid.