what is this and should I be worried?


Reefing newb
I noticed this tonight as I filled up my tank to check for leaks. I'm not sure if it was there before I added the water, and I'm not even sure what it is. It looks like its between where the two pieces of glass meet.


Doesnt appear to be between the glass, looks more like tape residue from when someone taped a background on, or glued something on. Shouldnt be a problem at all.
Hmm. Have no idea then. does the tank hold water? Where did you get the tank from? Do you know the person that had it before you? They could have used some strange kind of glue to hold it together when they sealed it with silicone is my only other guess. As long as it holds water I'd think it should be fine unless you want to go through all the trouble of scraping it down and re-sealing it. See what others think.
I dont think its a big deal, there seems to be enough sold hold. I have a new tank and i see a little bit of that as well. Never thought much of it...
Is this a use tank?If it is use and it is air,it should hold together on your 60g.


I bought a brand new 210 that had poor silicone job.Air bubbles down one side of the corner.It never occurred to me that this would be a problem.Sure enough,a couple of months later the seam at the bottom where the two planes of glass met separated.

My advice to every....always check the silicone work.Make sure there's no trapped air.
Reefs Right.The silicone is all thats holding those panes of glass together and there is quiet a bit of pressure in those corner joints when the tanks full of water,sand,and rock.
From the pic,there seems to quiet a bit of air trapped in that bead.I dont think I would trust my livestock and floors to it.
I dont know guys, that doesnt look like air to me at all. Looks more like if you squished glue together between 2 clear surfaces. Its just got that texture to it... And its opaque to whitish in color, I think someone glued the pieces together, then siliconed from the inside...