bulkhead sizing

[yakfishin]

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.

[mcgyvr]

Sure.. Just measure them with a tape measure or caliper..
You should be able to measure the outer threads and know what size pipe is in them now right?

[yakfishin]

Sure.. Just measure them with a tape measure or caliper..
You should be able to measure the outer threads and know what size pipe is in them now right?

By outer threads, those are the threads that the nut screws up on, correct? I can measure those. Is that measurement then going to be the same size as the drilled hole?

[mcgyvr]

By outer threads, those are the threads that the nut screws up on, correct? I can measure those. Is that measurement then going to be the same size as the drilled hole?

Yes. That will let you know approximately what size hole is in the tank..
The hole will be bigger but if you get a bulkhead with that same thread size then you know it will work

[yakfishin]

Great, appreciate your help!