Silicone Safest Strongest???

Time to reseal my 220 gallon aquarium, not because it's leaking but because it's drained and I know the seals are old.

I've read a lot of people use GE silicone 1 to reseal aquariums, but that it's not necessarily the preferred choice. When I read the label of the GE silicone 1 it says "Not for use in aquariums". After doing a little research I've found that RTV 108 silicone is the choice professionals go with. I can pick it up for 13 bucks a pop at Grainger.

Does anyone have input on which silicone to use when resealing an aquarium? Has anyone used GE silicone 1 or RTV 108, if so how long has the tank held water since then. Also, how long should you allow for the silicone to cure before exposing to water?

We got some interesting advice from Josh when resealing a 100 gallon metaframe. To do that, we used a Sikaflex product that is sometimes used in pond work and will cure to slate.

Josh advised we wait until it was tacky, fill it with water, then drain it right away and let it fully dry. Apparently the weight of the water presses the still slightly malleable silicon into the crevices and makes for a tighter seal.

Tank held water at last check, though we haven't officially set it up yet .

Thanks Becca, I think im gonna go with the rtv 108. I can post after I water test it.

Loktite silicone states that is aquarium safe. But I am glad that you posted the info on the RTV. I have been looking for that for a while now but could not find out which one was the right one.

I use the aqueon sealant. I ordered it right off Amazon. Ive sealed up 55, 45, 20, 10 gallon tanks with it. Ive never had an issue with leaking

Sent from my SCH-I200PP using MonsterAquariaNetwork App

From what I understand the RTV 108 is used by professional aquarium builders. I'm letting my 220 cure it's been roughly 4 days since applying the RTV 108. I will post the results of my first reseal job after my water test in about a week.

RTV 108 is incredibly strong. I compared a cured RTV 108 strip of silicone to a cured GE silicone 1 strip. The RTV 108 was easily two times stronger in comparison to the GE silicone 1 when attempting to rip apart.

I've never used it, but heard the RTV 108 mentioned on Cichlidae when discussing repair of very large aquariums. Glad you headed that route. Be careful to inspect the silicone in that is actually in between the panes of glass. If you see any bubbles, I'd seriously consider a complete tear down... which would be a horrific PITA, but my be worth the peace of mind on a big tank.

Definitely post back with updates.

Cheers.

Don't waste your money on the Aqueon stuff, it's the same as what you can get at Home Depot for half the price (just be sure to read that it is pure silicone, and doesn't have additives to inhibit mould around the bathtub). It's a quarter the price, and simply because it doesn't have the word "aquarium" or "Aqueon" on it.

The silicone is fine for smaller tanks, but when you are really considering the amount of pressure that a larger tank -- like a 220 -- is putting on those seams, I would consider the stronger RTV 108 or Sikaflex. They're going to last longer. The quick fill and drain is a real easy way to push it into your edges, too, and I use that when making photo tanks and such.

J

Luckily I've never had any issues with the tank leaking. When I stripped the old silicone off the seams the seals between the glass panes looked great! The tank is at least 15 years old so I've decided to reseal since it's drained for my DIY 3d background. I'm just about done. I will post pics toward the end of February. I appreciate all the advice ladies and gents.

O and lastly it's been my experience to always play it safe, whenever I build something I over build it. I will use the best stuff possible provided it's within my means.

I am skeptical of the quick fill and drain theory. When you fill the tank, the water pressure push the glass away from the sealant, not the other way to push the sealant towards the glass. You use your finger to push the sealant tight into the glass in resealing. The instruction says you must wait at least 72 hours to allow the sealant to cure before wetting. Adding water too soon will compromise curing. Submerging the sealant won't pressure it tighter to the glass, only makes it lighter to float away.

Hey Andrew, you wait until the silicone is surface dry before adding any water, which will prevent the water from effecting the curing (plus the contact time should be short). The water forces the silicone into the space between the glass -- and, you're right, it probably slightly pushes the glass apart, creating more area to push and seal. I've done it with every tank I've built, and never had a leak. It makes for a nice, clean, tight seal.