I have had a lot of questions about this 125 I bought. I have come to the decision, with much input and advice from you, to run a sump and a canister filter. So my dilemma is this," I have never drilled the back of a tank for bulkheads before and if I break the back panel doing it I am going to be real PO!" So question #1: How hard is it? and Question #2: Is there an advantage to bulkheads over HOB overflows? Once again any input is appreciated.