A chip in the glass is a stress section. When pressure is applied to it, you see the reaction. Enough stress and it will run. It will run until it is at the end of the panel and it has no other place to go. Your chip has run. Lucky for you it was a really short run. A nice circle straight to the nearest edge of the glass. It has no more potential stress and looks like it has no interest in going anywhere. If it was a chip that didn't run and the glass had not broken free, I would worry. Loose cannon and no telling where it would go.
Go to DIY and look at chips just like that left over from people drilling their own bulkhead holes. They all end up holding water and doing fine. I am sure I have a tank with a chip just like that and I was looking to see just now but there wasn't one easy to photo.
Options:
1) Fill it outside of your house with tap, or inside with RO. Let it sit for a few days and realize it is solid. If you are not sure, put a wave pump in it and set it to rock the tank back and forth. Just go and physically shake it until you feel safe. It is not going anywhere.
2) 180 grit paper, sand it smooth and make sure there are no other stress points (small scratches pointing toward the body of the glass) waiting to spring, go with 300 and then 500 if you like. It will only take another hour at the most. They have wet sandpaper at auto body shops up to 2k if you are wanting to really hide the thing. When I was 15 and the guy at the local glass shop taught me how to cut glass and seam the edges, we did it with 180 and that was good enough. Definately make sure that there are no sharp edges and it is not going to accidentally cut anyone.
3) Take it to a glass shop and pay them $100 to take 180 and possibly 300 grit to it and smooth out the area. They will tell you that it is the best they can do and that they cant guarantee anything that does not go through their polisher because of all of these reasons they have that will scare you.
4) Have the panel replaced for more money than a new tank costs. There is still a chance it will break, like all tanks and all glass, but it might help you sleep at night.
5) Put it on Craigslist for free and get that Demond seed out of your home! Go buy a new one with no scratches or chips and hope that it is not one of the small percentage of tanks that just breaks anyway.
Sorry for being kind of a smart ***, but I really think you don't have anything to worry about. I there is a legitimate concern about structural integrity when you get to 30" high, and a scratch from a wedding ring that hits an edge would raise a red flag for me. However, since 1984 when I was shown what a bullet chip is, I have not seen one that has been resolved begin to run again. One that is sitting on a silicone supported seam really don't pose a threat. My biggest concern is that no one gets cut on it. For some reason I, and people around me like to feel edges of things. Knock the edge off of it with 180. No one gets cut and you are fine.
If I saw the photo wrong and the chip has not resolved its self and is not free, your need to free it! It is a time bomb! Take a screwdriver to it and pop it out. I have no experience with epoxy and glass repairs. I have seen one done on a windshield. If someone does have experience with that, I would appreciate them sharing their knowledge.
