Leak testing question

Mr. Wiggles · Dec 31, 2019

Hi everyone! Apologies if this is in the wrong forum, I suppose the main DIY project has already been finished...
I recently had a leak on my 60g cube, from the bottom right corner, if that matters. So, I spent the day yesterday removing and resealing all the inner silicone. I'm fairly confident that I did a good job, and really took my time getting all the old silicone off (razor, acetone, razor again, checked with a flashlight, rubbed remaining hazy spots with more acetone, then took a razor to it again). Anyways, by tonight it will have been 32 hours of curing time, and since tomorrow is my day off work, I'd like to start leak testing it while I'll be around. Here's the problem though: I live in an apartment, so I don't have a garage or yard in which I can do this; I do have a balcony, but it's a MN winter and I don't dare freeze my precious silicone! I am planning on putting the tank on its stand next to my bathtub, so I can easily drain it into that if need be. I bought a bunch of leak detection alarms as well. If all goes well, I will have it filled around 9:30pm tonight, and will be able to be home/near home until 1:30pm Thursay, so about 40 hours, maybe a bit less. Is this enough time for a reasonably confident leak test? I'm scared of leaving this tank full while I'm at work, and would feel better draining it before leaving...then again if I'm feeling confident about the tank I shouldn't worry enough to drain it. So I actually have a few questions:
1. How long would you leak test this tank?
2. If I wanted to test for more than 40 hours, would it be ok to drain it for the day, then refill when I'm home, then rinse and repeat until the cumulative number of hours the tank has seen water reaches, say, 72? Or is 72 straight hours different from 72 cumulative hours?
3. I'm not afraid of a small leak while I'm away so much as a massive burst in which all 60 gallons dumps onto the floor in a short amount of time. If, by 40 hours this doesn't happen, is this a reasonable thing to fear?
Thanks in advance for you help!

Edit: I should add that the frame has a pretty heavy rim on top and bottom.

Billdogg · Dec 31, 2019

FWIW - the seal you replaced is cosmetic only. It is not the structural seal that actually keeps the water in the tank. That seal is between the glass panels themselves. Although you may have delayed it's leaking for awhile, it will almost certainly leak again in the same area. To actually fix the leak, all 5 panels must be separated, cleaned, and reassembled. If you've never done it before, it is not any easy task at all.

If it were mine, I'd replace the tank and sleep well at night.

Mr. Wiggles · Dec 31, 2019

Billdogg said:
FWIW - the seal you replaced is cosmetic only. It is not the structural seal that actually keeps the water in the tank. That seal is between the glass panels themselves. Although you may have delayed it's leaking for awhile, it will almost certainly leak again in the same area. To actually fix the leak, all 5 panels must be separated, cleaned, and reassembled. If you've never done it before, it is not any easy task at all.

If it were mine, I'd replace the tank and sleep well at night.

Here’s what I don’t get; scouring the internet, people seem to fall into two camps, one that says what you just said, and one that says that what I did is sufficient. Why is this? It seems to me like it ought to be a pretty black-and-white issue...

Bruce60 · Dec 31, 2019

Mr. Wiggles said:
Why is this? It seems to me like it ought to be a pretty black-and-white issue...

It is difficult to identify a black and white issue with reef tanks aside from something like alive and dead.

The real answer is that it depends. How much has the underlying structure of the tank been compromised? Where is the leak originating? - not always the same spot it appears to exit the tank. Did you actually seal the origin of the leak? Is there other stress on the structure of the tank that will exacerbate the situation? There are multiple factors that are unable to be evaluated to provide a clear answer.

If you do as proposed by Billdogg, it will work...if you do it correctly. I suspect that it is worth the cost of a new tank compared to the time and effort it would take you to effect the definitive repair.

If you proceed along your current path, the passage of time will provide increasing confidence that you have fixed the problem in your instance. However, there is always the chance of failure. Heck, there is for new tanks as well. You need to balance a guesstimated increased risk for your repair job compared to a new tank versus the cost of a new tank.

If I were you, I would just go out and purchase a new tank. The location of the leak is, in my opinion, a bad sign.

If you want to give it a whirl and see what happens, I would give it a minimum of a week with fresh water only to see if it holds water at all. I would want a full day checking it frequently to start - fill first thing in the morning and hang out at home - winter in MN is a good excuse to stay in. If it held water for a week I would feel comfortable enough to try...if I didn't have the money for a new tank. But I would always have the worry in the back of my mind, which brings me back to buy a new tank for peace of mind.

Mr. Wiggles · Dec 31, 2019

Bruce60 said:
It is difficult to identify a black and white issue with reef tanks aside from something like alive and dead.

The real answer is that it depends. How much has the underlying structure of the tank been compromised? Where is the leak originating? - not always the same spot it appears to exit the tank. Did you actually seal the origin of the leak? Is there other stress on the structure of the tank that will exacerbate the situation? There are multiple factors that are unable to be evaluated to provide a clear answer.

If you do as proposed by Billdogg, it will work...if you do it correctly. I suspect that it is worth the cost of a new tank compared to the time and effort it would take you to effect the definitive repair.

If you proceed along your current path, the passage of time will provide increasing confidence that you have fixed the problem in your instance. However, there is always the chance of failure. Heck, there is for new tanks as well. You need to balance a guesstimated increased risk for your repair job compared to a new tank versus the cost of a new tank.

If I were you, I would just go out and purchase a new tank. The location of the leak is, in my opinion, a bad sign.

If you want to give it a whirl and see what happens, I would give it a minimum of a week with fresh water only to see if it holds water at all. I would want a full day checking it frequently to start - fill first thing in the morning and hang out at home - winter in MN is a good excuse to stay in. If it held water for a week I would feel comfortable enough to try...if I didn't have the money for a new tank. But I would always have the worry in the back of my mind, which brings me back to buy a new tank for peace of mind.

Makes sense. Of course I’m uncertain as to whether this will in fact work, hence the leak test. My impression is that the silicone was simply old and dried out, since the tank is 9.5 years old and has never had water in it.
I’ll test it out for a week. Best case, the shop I bought it from will take it back for a display and give me a discounted price on a new one. Thanks!