I'm converting my 29g biocube to a 90 gallon. I'm going to have a sump on it and I am unsure of the best way to drain water from the tank to the sump. I had a 65 gallon before and had two bulkheads drilled in the tank and the drain to the sump was very loud. I would like to avoid this! If I was to get an overflow box, would there need to be holes drilled in the tank for this? Or does it go over the rim? Anyone have experience with these? I've never used one and I'm interested in learning more.