How big a leak concern?

[Old Dog]

I picked up a used aquarium. The stand has been wet one too many times and needs to be rebuilt. Before investing much time into it, I filled the 175 gal aquarium to the top and put a heater in it. I let it sit for a week. No leaks.

I was in my LFS last week. Owner started telling me about getting a call in the middle of the night from a new account that had a big leaking tank. He said it looked like previous maintenance had been scraping into the seal when cleaning and eventually, the seam separated. Had a video of him pressing the glass at the seam and can see the disbond.

So, I go back home and take a good look at this aquarium. Here are pics of the two front seams. How worried should I be if I set it up? If I stay away from it with the scraper, will it still separate over time from the pressure? Since it is disrupted, can coralline algae grow and push against lifting the seal?

Reading up on seal repair seems misleading. People saying silicone does not adhere to silicone, the seal has to be stripped all the way down. Others talking about fixing a leaking aquarium by draining the tank to below the leak and applying silicone.

 

[WVNed]

Large tanks have to be stripped and rebuilt with new silicone. The amount of weight and pressure on the glass is a great deal more than a small tank. You would be amazed at how much an 8 foot piece of glass bows in the middle. Best not to think about it.
The only silicone that matters is that between the 2 pieces of glass. The rest is window dressing to make the tank look better.

 

[Old Dog]

Thank you. From the outside looking in, everything between the plates looks fine. The overflow boxes have a couple of areas with small leaks back into the tank that I can see easily looking through the glass. Makes me think he corner seams then are still good since it's a dark black solid line.

 

[WVNed]

I have only had one fail. A 55 I had for 20 years. It didn't leak. The bottom front seal gave way and dumped the water in the floor by bowing the glass outward. The weight on the glass went down as the water came out so it held enough in the end for me to get the fish into buckets. A sound you never forget.

 

[Little c big D]

Are you comfortable re sealing the tank yourself? my 90g was chipped up like that and never leaked. If youre nervous about it then re sealing for piece of mind is a great idea.

 

[Klyle]

I don't know much about siliconing aquariums but I would imagine resolving the issue now, since there isn't any water / fish / corals in the system is going to be much easier than resolving the issue at say, 3am next Christmas Eve when there is water gushing all over your floor and fish flopping around on the ground! This hobby is already difficult enough without starting out with one foot in the grave.

 

[Little c big D]

I believe the tank will hold but like you said. next christmas, or some other perfectly timed disaster would be when it happened. Also it would look better and make you feel better.

 

[Old Dog]

If it means stripping the tank down, separating the glass plates, and resealing the interfaces, this tank is not worth it. If it's just putting a new bead of caulk over the old either in the places where it is thin or along the entire length, that's something I am relatively comfortable with. But, earlier post from WVNed is that it would need complete tear down.

 

[WVNed]

You are gluing things together. It is the glue in the space between them and not that all over the top that holds them together.

 

[Old Dog]

I appreciate all the comments. If I am understanding correctly, what is being said is that the caulk I have pictured may be ugly, but it is not going to make or break the tank. It's whether I think the actual sealant between the plates has any issues.

 

[Lbrdsoxfan]

My 50 gal cube looked like that. It held water for over 2 years. When I upgraded to a 120g I carefully scraped off the corner exposed silicone, the 'visual' parts. I then reapplied the silicone and then I filled it to check for leaks, no leaks, it looks way better and I put it in storage. I'd use it again in a heartbeat.

 

[Brian_68]

I would not use it. It will hold water, until one day it may not. It could be a small drip or a gusher that can cause thousands in damage to your house and loss of inhabitants. Used tanks are not worth the worry for me unless in the basement over concrete near a drain.

 

[Old Dog]

Was at my LSF today. As they were talking about two maintenance accounts that leaked in each of the last two weeks, I showed them these pictures. Their suggestion was to cut the caulk on the interior, clean it up and reapply caulk. Is it being said that the caulk in the corners and the bonding between plates are separate?

I think that is what is confusing me. I thought plate bonding and the caulk in the corner are one and the same.

 

[luvinreefer]

I’m with Brian. Its not worth the risk. If I’m going used it better be in really good shape and steeply discounted. There’s to much that can go wrong in this hobby already. No way am I going to worry about a complete tank failure causing potentially $10,000’s of dollars in damage to save a few hundred or even $1000,’s up front.