Pool filter pipe leak

Hey folks,

I came to this forum in hopes of getting some advice. We have a pool guy but each time we ask him to look at and repair something it takes about 2 weeks just to get an estimate, so I'm thinking I might just try to handle this myself.

Over the past two days I've noticed that our pool hadn't been operating normally. When I looked at the filter, I noticed a small leak coming out of the upper inlet tube (hopefully I have the terminology right). I turned the pool off to make sure the problem didn't get worse, but today I wanted to take a picture of the leak so I turned it on and about 2 seconds later the coupler blew right off and water sprayed everywhere. After it blew off, there was a black rubber o-ring hanging on the threaded portion of the pipe. I have no idea if this is something that just came loose or if I need to replace the piping. I've attached some photos that hopefully illustrate the problem.

Any advice on this is very much appreciated!

Thanks in advance,

Kris

Here are the photos:

http://i.imgur.com/S26hWIn.jpg

http://i.imgur.com/1n1683p.jpg

http://i.imgur.com/3jjH2An.jpg