Best Aquarium Silicone Compared & Reviewed 2024

Silicone is important when it comes to glass aquariums.

It holds the tank walls together and provides waterproofing; it’s what keeps the water inside your tank and off of your floors.

So, if you’re trying to reseal a leaky tank, or build a new one from scratch, having the right silicone is absolutely vital.

Today, I’ll go over the three best aquarium silicones on the market so you can make an informed decision on which one will work best for you.

Quick Overview

I think the GE SCS 1200 is the best choice. It might be a little pricey, but it’s high strength and short cure time make up for this.

In the long run, it’s cheaper to spend a bit more on silicone than it is to replace your whole tank/water damage if it busts open.

Last update on 2024-04-24 / Commissions Earned / Images from Amazon Product Advertising API

Seams vs Seals, There’s a Big Difference

Right off the bat, let’s get some terms straight:

• Seams – the line of silicone in between two pieces of glass that adheres them together. Seams bind the walls of the aquarium together and bear the weight of ​​the glass and water.
• Seals – lines of silicone inside the aquarium that provide waterproofing and help protect the seams being stressed by things in the aquarium, like substrate or hardscape. Seals don’t bear weight, but they keep water from leaking between the pieces of glass.

Not All Silicones are Created Equal

Do not believe internet sources that tell you that all 100% silicone products are the same!!

Many, many different formulations are considered “100% silicone.”

Some have more tensile strength than others; stronger silicones are a better choice for seams since they can withstand more pressure.

Best Aquarium Silicone Reviewed

I based my decisions about ranking these products on three criteria: tensile strength (expressed as pounds per square inch), cure time and price.

GE SCS 1200

• PSI: 480
• Cure Time: 48 hours 
• Price: $$$

This silicone would be my first choice for either making repairs or building a new tank.

It has a 48 hour cure time, a full 24 hours less than its closest competitor. It can withstand up to 480 PSI of pressure, more than strong enough to keep tank walls together.

The only downside to this silicone is the price. The GE silicone, and its closest competitor, are much pricier than the third place silicone.

But, the short cure time and comparable strength make this the best choice, in my opinion.

GE SCS 1200 is often used by companies that build new aquariums, a fact that speaks for itself.

Last update on 2024-04-24 / Commissions Earned / Images from Amazon Product Advertising API

Momentive RTV 108

• PSI: 400
• Cure Time: 72 hours
• Price: $$$

Momentive RTV 108 comes in second. 

It is just as expensive as the GE SCS 1200, but has a little less strength and an additional 24 hours of cure time.

Don’t get me wrong, it’s suitable for both building new tanks and repairing old ones, it’s just that the GE SCS is a little better.

Last update on 2024-04-24 / Commissions Earned / Images from Amazon Product Advertising API

ASI Aquarium Sealant

• PSI: 520 PSI
• Cure Time: 7-10 Days
• Price: $

So, our final contender is ASI Aquarium Sealant. It is the strongest of the group at 520 PSI. It is also much cheaper than the GE or Momentive silicones.

However, it can be hard to get a hold of. Most live fish stores don’t carry it and neither do hardware stores. You’ll need to order it online. 

But, the biggest problem with the ASI silicone is the cure time. Depending on the temperature, it can take up to 10 days to cure. 

This is not the stuff to use if you’re trying to make a quick repair on a tank that’s time sensitive.

I would say this silicone is best suited to building new tanks, rather than repairing old ones, if time is a factor.

Last update on 2024-04-24 / Commissions Earned / Images from Amazon Product Advertising API

What About GE Silicone 1?

GE Silicone 1 is used by some aquarists for seals. It does not have nearly enough tensile strength to be used for aquarium seams.

I can see how the low price and wide availability of Silicone 1 can make it a tempting alternative, but I don’t think it’s a good idea.

Some people use it for seals and get away with it, but the manufacturer specifically states that Silicone 1 should not be used for underwater applications.

Put that together with its low tensile strength, and I cannot in good conscience recommend Silicone 1 for sealing an aquarium.

Final Thoughts

When it comes to sealing or building a fish tank, you’ve got to make sure that you use the right product.

Just because a sealant says that it’s 100% silicone does not mean that it is suitable for aquarium use. 

I think the GE SCS 1200 is the best choice. It might be a little pricey, but it’s high strength and short cure time make up for this.

It’s a whole lot better to spend some extra on silicone than it is to replace fish, plants and possibly your living room floor, if your tank busts a seam.

I hope you find this article helpful.

I wish you and your fish the very best!