5 Gallon Tank Silicon Seal Failing On Older Nano Tank

[VassalofUlmo]

I have a 5.5 gallon aquarium stater kit from PetSmart. I think I bought it about 8 years ago. The silicon seals are failing. They're starting to peal off and algae is growing underneath in some places. So far, I haven't had a problem with leaks but I presume that this problem could develop later.

Also, do failing seals release toxins into the water, or are future leaks my only concern? I've had several unexplained fish deaths.

What are the recommended next steps in my case? I would prefer to repair the tank, but I'm not sure if it's worth the time and money.

 

[Kwikfab]

I have a 5.5 gallon aquarium stater kit from PetSmart. I think I bought it about 8 years ago. The silicon seals are failing. They're starting to peal off and algae is growing underneath in some places. So far, I haven't had a problem with leaks but I presume that this problem could develop later.

Also, do failing seals release toxins into the water, or are future leaks my only concern? I've had several unexplained fish deaths.

What are the recommended next steps in my case? I would prefer to repair the tank, but I'm not sure if it's worth the time and money.

I'm not familiar with re-sealing so I'm sure others will chime in.

But a 5.5 gallon tank is so small, and would be really affordable to replace.

 

[Fishyfreeonz]

I have repaired 7 tanks with silicone damage on the inside that didn't leak. I cut the remaining silicone out and removed all the silicone from the glass surfaces without damaging the actual seal between the pieces of glass. Then wipe it down with alcohol or acetone to remove oils and reapply silicone. I've even replaced frames on older tanks. It doesn't cost much money and it's sorta fun. Out of my current 8 tanks I've only purchased one new (2 days ago lol) and the only other one I didn't repair is acrylic.

The key to a good silicone repair is removing every trace of silicone from the glass surface with single edge razor blades because silicone won't stick properly to old silicone. Also no solvent will dissolve silicone do it must be removed by mechanical means. I find replacing the razor blade about every minute or so produces the best results.

 

[Fishfur]

Provided you take care not to damage the joint between the edges of the panes, replacing that inner silicone seal isn’t difficult but it is a bit tedious and fiddly to remove all the old silicone because, as Fishyfreeonz said, the new silicone just won’t stick to old cured silicone.

So it is essential to get every trace of the old silicone off. I find a vacuum with the edge tool attached really helps clear away the little pieces of cut silicone that end up everywhere.

Buy a big box of blades for a razor scraper. You really will need to replace them frequently.

I have used a stainless steel scrubber occasionally to get stubborn bits of silicone off the glass but I don’t press hard like I would if I was scrubbing burnt whatever from a cooking pot. So far there have been no scratches from using the SS scrubber but it is better not to have to use it.

If I am taking a tank apart to replace a broken pane then sometimes the SS scrubber works better on the narrow edges of the intact old panes than a razor blade does. Those edges are not always particularly smooth.

When you are ready to apply the new silicone, use strips of masking tape first to neatly outline all the joints. It will make it much easier to do a quick and very neat job.

Run the bead of silicone along each joint and then use a fingertip or gadget to press it into the corner & spread paper thin edges just over the tape. Soon as you finish, pull up the tape and you get super neat, very clean, very straight edges to all the new silicone.

Any smears or blobs that end up where they shouldn’t can easily be removed from the glass after they cure. Best to let them be until after the silicone cures.

 

[Sewerrat]

Would just buy a new tank seals can be redone but tank would would need to be empty and dry would take about same effort to just transfer everything from that tank to new. Could always redo seals later at your convenience if it's already empty.

 

[AquariumGeek]

Also, do failing seals release toxins into the water, or are future leaks my only concern? I've had several unexplained fish deaths.

I do not think that cured silicon would leak any toxins into the water. What kind of fish are in the tank, and what are your water parameters (ammonia, nitrite, nitrate, ph, gh, and kh)?

 

[Fishfur]

I have a 5.5 gallon aquarium stater kit from PetSmart. I think I bought it about 8 years ago. The silicon seals are failing.

Also, do failing seals release toxins into the water, or are future leaks my only concern? I've had several unexplained fish deaths.

What are the recommended next steps in my case? I would prefer to repair the tank, but I'm not sure if it's worth the time and money.

Those seals are not what keeps the glass panes together, they’re just a bit of extra insurance against a leak in the seal between the glass panes which does keep the tank together.

Very high end tanks tend not to use that inner bead of silicone but do use thicker glass and best quality manufacturing techniques.

Old silicone doesn’t leach anything into water anymore than new silicone does, so far as I know.

But a crumbling inner bead of the stuff can drop bits into the water that are a bit unsightly.

Any sufficiently deteriorated plastic may do that including the plastics used to make filters, parts of heaters, pumps, airlines, and even decorations.

Whatever might be causing fish deaths, it isn’t the silicone unless maybe a fish gulped down a chunk big enough to cause an obstruction in its digestive tract.