Water return woes

[btcrazee]

I am so disgusted I could scream. I have a 24 ft above ground pool that suddenly began to lose water. I called out the local pool company and they told me there was a hole. Yes, but as anyone can see, that hole is above the water line. I was thinking maybe it was well below the water as I saw nothing and started to pump water out. I had to leave it for a couple days and noticed that the water level was the same. I called them back out and asked them to check the skimmer and return. Evidently they checked it for leaks on the outside which I could see myself no water was leaking...DUH. So I decided as the next step to refill the pool in increments. I put water in, marked the level on the steps with a magic marker and let it sit over night. When it got up over the bottom of the return, bingo, it leaked down. I think it is losing water at the bottom of the return. I think the water is running out between the liner and the wall, and running out under the edge of the pool. My burning question is, how do I get this thing off? When I get it off does it need a bead of silicon, a gasket or what?? I am not real mechanically inclined and see no obvious screws like in the skimmer and have found nothing online to give me a clue. TIA

[Vinyl Master]

Here are a couple of things you can try. The return fitting is held onto the wall with a large octagonal nut that threads on the back of the return fitting try to tighten it with a large wrench. You could also try some under water silicone around the outside of the return faceplate from inside of the pool. Good luck