Okay so I bought a used tank. Its a 50 gallon rimless. I just went to fill it to leak test it today, I got a few inches of water in there and then noticed this corner didnt look right. Its holding the water fine so far but I didnt fill it up any higher yet just incase. Is this just a result of a silicone job or do you think the glass pane is fractured? It looked fine empty as far as I can remember.