I bought a top filter for my aquarium. It overflew twice most probably due to an incorrect setup. I had my desktop PC under the aquarium and any overflow incident was a serious issue. It was then I felt the need for something similar to a trip switch. The bucket with the money plant serves as the trip switch aka the overflow protection. Water coming from the filter + Overflowed water from the water (worst case) will safely pass through the outlet of the bucket.