What kind of fitting do I hook this up to?

It's smooth, not threaded and about 1.25 inches.

Purchased this 8.9 gallon Ada from another nano reefer. I want to hook up a sump to it and it has already been drilled. I need to fit the outflow part from the tank and I attached photos, what do I need to look for at the Home Depot to fit a hose to it?

This is the outlet attached to the bulk fitting inside the overflow.

 

Looks like it's a socket fitting. A side shot of it would help.

If so, you'll need to get a socket x thread adpater and then a hose barb that matches your tubing size. You'll need to glue the socket x thread adapter into that fitting on your tank. Make sure to use the Rain-R-Shine PVC cement.

 

Thanks, so basically all I need is some of that cement, a proper barb, and something like this:


http://www.sprinklerwarehouse.com/Dura-Sprinkler-PVC-Male-Adapter-p/436-132.htm

 

Yep that'll do it.

 

Actually it seems like this would be perfect for a 1 piece solution
Amazon.com: Lifegard Aquatics 1-Inch Slip Insert Fitting: Pet Supplies