Can I reseal only part of an aquarium?

[Carefree_Dude]

I'm prepping an old 55 gallon and I noticed the silicone is slightly damaged towards the top. Tank still holds water as it currently is. It's it possible to only re silicone this small 3 inch section or do I need to do the whole aquarium? Do you think I'm safe leaving things as they are since it still holds water?

 

[Ulu]

New sealant won't stick to cured silicone. It will always leak at the top & bottom of the new patch.
This will probably last a few more years before it begins to seep.
Lots depends on how level and square it all is.
If you want safety, you need to scrape the inside out with razors, clean with solvent and reseal the whole inside at once.
Then let it cure several days to a week before filling.

 

[FishEZ]

I have to agree with Ulu since I recently tried to do a partial re-seal on a 30G and after i did it, it leaked worse than before i started. So now I'm back to doing the entire tank as i should have done to start with.

 

[Ulu]

There's only one way to reseal an aquarium without removing the old silicone.

You have to clean all the glass and silicone off perfectly clean. Then you apply a Band-Aid of silicone to the glass over the entire existing silicone seal encapsulating it to the glass completely. And to the polystyrene if you have a plastic top trim.

This will work if you get the glass and silicone perfectly clean before you do it but the problem is that you have to get all the moisture out too. Moisture trapped between the glass and existing silicone will tend to Leach out and spoil your seal.

Anyhow there is so much cleaning involved to do that that is totally worth scraping the inside of the tank. You need a $2 box of razor blades and a tube of silicone and a spare afternoon.

Or maybe two spare afternoons depending on how strong your hands are because it is physical labor.

 

[skjl47]

Do you think I'm safe leaving things as they are since it still holds water?

Hello; My answer depends on where the tank will beset up. In a room in the living area of a house on hardwood floors or even worse on carpet then a partial fix would be a big worry. On a slab or in a basement or garage then I might try it.
I have total resealed tanks in the past and had good results but also had to do it a few times with a few tanks. Even a total reseal has an element of risk.

 

[Carefree_Dude]

I have resealed aquariums a few times before, but it is just such a large hassel. I'm considering just buying a replacement as 55 gallons are pretty cheap, and i'm not sure if the time and effort it will take to reseal is worth it especially since i'd have to get all the sand out of the aquarium too.

 

[skjl47]

I have resealed aquariums a few times before, but it is just such a large hassel. I'm considering just buying a replacement as 55 gallons are pretty cheap, and i'm not sure if the time and effort it will take to reseal is worth it especially since i'd have to get all the sand out of the aquarium too.

Hello; I have always thought it worth the effort for a number of reasons. Often it was the money involved but you sound flush so I will skip that one.
If you trash a tank it becomes just more trash before that for sure is necessary.
Glass takes energy to make so in a sense you may be able to extend the service life of that glass. I guess we could add the energy used to ship stuff around as well into the figuring. Of course these green things may not be every one's cup of tea but I do think of them sometimes.

Maybe the last thing is a sense of accomplishment when getting it right. Not sure why but it feels good. But it is a lot of effort for sure. Getting the sand out has been one of the easier bits of the process for me.

 

[pops]

seal does not look that bad. I have ran much larger tanks than that with allot worse looking cove seal. Keep in mind the silicone cove is not the seal of your tank. its the silicone between the glass. That being said no you can not patch, you can remove the existing silicone cove "NOT BETWEEN THE GLASS JUST THE COVE" thats a rebuild. done a few times, bit of a pain but hey, 18 pack of beer, or a good bottle whisky take a 55g about 4 to 5 hours start to Finnish. there are some great DIY vids out there that will point out finer points as in prep is everything.

 

[nataniah]

I read this forum too late I am very new to fish keeping and I was planning on upgrading my 10 gallon to a 30 gallon. I got the tank today and was told the top quarter of the tank leaks but he said if I reseal it it’ll be fine. I just finished sealing it and was looking for tips when I found this. I tried my best to go over it again and even covered the old silicone edges so it would hopefully “connect” them. Should I just scrap it tomorrow when it’s fully cured? (Yes I am aware it looks aesthetically terrible)

 

[jjohnwm]

Honestly, the tank in post #1 looks to my eye to be completely safe for use. The silicone between the glass panes is what holds the tank together and provides structural strength. It's usually a continuous seal that maintains the waterproof integrity of the tank as well; the extra little concave bead that, in this pic, shows a bit of a ragged edge, is there just as an added insurance against leaks. If this tank doesn't leak now, I doubt it will at any point in the foreseeable future if properly set up on a flat, level stand.

N nataniah , sorry to say but the spot where your old silicone meets the new is a problem. However, it looks as though you scraped off the old silicone from the upper half of the corner and then re-sealed? Definitely the wrong way to do it, but it's done now so why not try it out? Any leaks will likely be visible within a day or two.

Whenever you apply silicone, you really have one good chance to make it smooth and neat, right when it is first applied. If you keep poking and squeezing and fiddling on the bead, trying to get it right...which is what it looks like you did...it just gets uglier and uglier. Same if you wait more than a minute or so to "tool" or work the surface. Lay it down, wet your finger and swipe across it once. Practice makes perfect.