GE Silicone 1

[Ricksza]

A lot of people have been asking about silicone for the aquariums. Going by the many recommendations across the internet I used GE 100% Silicone 1. After someone pointed out to me the under the instructions it says "Not for underwater/aquarium use", for my own peace of mind, I contacted Momentive (manufacturer who makes it for GE). Their response was: "We would recommend removing the silicone. It is not designed for aquarium/below water line use because it may fail when submerged for continual use and harm your fish". What they mean by fail, I don't know, breakdown, crumble, lose adhesion? Since it's not in a critical area (used to glue a divider in a tank), I'm going to just keep an eye on it, but I will not be using it again in any of my aquariums. Take it or leave it, this is my opinion.

 

[Byron]

I was advised by experienced hobbyists that silicone not intended for aquarium use can not only fail but leech toxins into the water, and this is probably what the manufacturer meant by "harm your fish."

 

[Colin_T]

Different types of silicon are made for gluing different substances ranging from metal, ceramic, glass and anything else. If you use a ceramic or metal silicon on glass there is a big chance it won't hold.

If you use a glass silicon that is designed for bathroom showers, then it might have a mould inhibitor in it that can leach into the water. And the shower silicon might not hold together when kept underwater for a period of time.

Any silicon used for an aquarium should be designed for glass and specifically state "Suitable for Aquariums" on the packaging. If it doesn't say suitable for aquariums, you risk the fish being poisoned or the tank coming apart.

If gluing an aquarium together you need to ensure the glass is clean and free of oil and dirt because that can prevent the silicon sticking to the glass.

When silicon fails it can either break down or just peel away from whatever it is glued to. It can dry out, crumble, crack and change colour (it usually goes cream or white when it it failing).

 

[Fishmanic]

I used dap 100% clear silicone and also GE clear silicone I for adhering rocks together. Over time it does seem that the bond loosens as sometimes I have had to clean off the old silicone and reapply. If you do decide to use silicone caulk for rocks, ornaments etc , make sure it is clear and doesn't contain any mold or mildew inhibitants and be sure to let it cure for at least 24 hours...48 hours would be even better and use it sparingly.

For assembling an aquarium, I would go with only silicone that says that its safe for aquarium use. Wouldn't want to see a seam fail on an aquarium. For constructing aquariums, it's best to go with brands recommended by people that assemble aquariums as a business.

 

[Ricksza]

The GE 100% Silicone 1 doesn't list any mold inhibitors and it wasn't used for any structural purpose, just to hold a divider in place. I'm waiting to hear back as to how it could fail and why it may harm fish. It could be that it doesn't have the strength as regular aquarium silicone, it felt more flexible.

 

[FishGuest5123]

I use the Dap 100% silicone that says safe for aquariums. It holds my dividers just fine.

 

[Colin_T]

If it doesn't have mould inhibitors in and is only used to hold a divider in place, it should be fine.