Leak testing this used tank and found these bubbles and a crack. Is the tank screwed?
Ah good point, I should have posted the dimensions. It's 29 gallons (106L), 76.2L x 30.48D x 45.72H (lengthwise is 2.5ft).How large is the tank, as the weight of the water within makes a huge difference? I am definitely not an expert, but I wouldn't worry about the bubbles. That if probably just a little trapped air from when they glued the pieces of glass together. I would be a little more worried about the chip in that first picture, but I do not think that would result in failure of the tank. I would fill the tank outside somewhere for a week or two and if there is no leaks, go for it. Hopefully someone with more knowledge of the physics of glass will come along with better info.
It's EVA foam mats, cut to fit. (I am bad at cutting)Just curious. What kind of mat is that underneath the tank?
Thanks for the input. That gives me some confidence. This tank definitely looks like a DIY job, the edges are butted unevenly - 2 edges are actually butted and the other two are.. not so even. I filled it halfway and let it sit for 24 hours and it was fine, and yesterday I filled it a little more so it's around 75% full. I'm still waiting for parts to build my sump so I can let this sit for a while. Fingers crossed.Looks typical for a used or DIY rimless tank. Also typical in the entry level commercial tanks like Aqueon. Just based on my own experiences, I would say that it is perfectly fine to use.
For some additional data points:
I had a 29g tank with a glass chip right in one of the lower corners. I water tested it for a couple of weeks and it was fine. Then plans changed and I decided to try and sell it, and it sat with water in it for another 6 months, with no issues. Your chip looks to be on the outside edge, and doesn't appear to be deep. I would just turn that edge to the back and forget about it.
I also had a entry level commercial 50g for a couple of years with bubbles in the silicone of the joining edges, just like the ones in yours. Mine were all in the corners (black-rimmed tank so I couldn't see the bottom seams). Zero issues.
I also had a 130g tank made by a DIY tank builder back in 2009ish. When I moved out of my parent's house, instead of moving it with me, I just gave it to them. It's had small bubbles in every joining edge of the silicone since I got it. I was inexperienced and thought it was normal. Anyway, it's been up and running since the day I got it. Zero issues. It actually outlasted a commercially made 45g hex tank, that one was maybe 7 or 8 years old before it finally blew a seal.
Given your space and situation, I would fill it with maybe 5-10 gallons for a few days to check for leaks. Measure the bubbles as minorhero suggested. Then fill to 2/3rds for a few days. Check for leaks and measure bubbles. Then fill to regular water level for a week or two, check for leaks and measure bubbles. If there are no changes, I'd say you're in the clear.