I was thinking sincer my 50 will be going through A LOT of new changes to see about drilling it in the back. So now i have a overflow at the top but would really like a bulkhead. So how would i go about doing this, my tank is acylic so it is easier to drill then glass i believe. So what size would be good, i have a 15 gallon refugium and a mag 7 as my return.