Need help, aquarium repair

[Willylumplump]

180 gal tank, running 6 years. One of the overflows is loose and not completely siliconed to the glass, causing water to run through, and less surface movement on that side of tank. Is there any way to apply silicone and/or reseal without draining the tank.
I can not drain

 

[Biglew11]

i ran across this. Not sure if it's safe for a reef tank.
https://aquabondadhesives.com/aquaflex-underwater-sealant

 

[Willylumplump]

thanks for the reply. I had done searches here. serveral "emergency" threads, but no answers. I'm surprised no one has come up with anything to this point. My daughter has recently taken a liking to cleaning the glass, and always afraid she will hit the corners. The overflow was a little loose before