I have an Oceanic 220 reef ready aquarium that I purchased probably around 2006. I just ordered it standard, nothing customized. I am at the point where I need to update my sump and plumbing. My question concerns the bulkheads. Is there a way I can now tell the size bulkheads I need that will be replaced? I can't remember the size holes that were drilled in the overflow. Is there a way to tell prior to my taking things apart? If worse comes to worse, I may order several different size bulkheads to make sure I will have the correct size on hand, but would like to avoid it if possible. Thanks.