How to Choose the Right Super Glue for Your Reef Tank
If you’ve ever gone looking for super glue for your reef tank, you’ve probably noticed there are quite a few options. Even within the BRS lineup, you’ll find General Bonding Super Glue, Maxi-Cure Extra Thick, and BRS Extra Thick Gel.
They’re all cyanoacrylate super glues, so the biggest difference comes down to one thing: viscosity.
In other words, how thick do you need the glue to be?
A thinner glue can flow into tight joints and small spaces. A thicker glue stays where you put it and does a better job filling uneven gaps. Somewhere in the middle is a good general-purpose option for fragging and everyday reef tank use.
Quick Comparison
| Super Glue | Consistency | Best For |
|---|---|---|
| BRS General Bonding Super Glue | Thin, almost water-like | Tight-fitting rock joints, cracks, and seams |
| Maxi-Cure Super Glue | Medium-thick | General fragging and everyday reef aquarium use |
| BRS Extra Thick Super Glue Gel | Very thick gel | Uneven surfaces, larger frags, rockwork, and underwater mounting |
If you just want the quick answer, Maxi-Cure is the most versatile general-purpose option. Go thinner when you need glue to flow into a tight joint, and go thicker when you need the glue to stay in place or fill space between uneven surfaces.
BRS General Bonding Super Glue
BRS General Bonding Super Glue is the thinnest of the three. Its consistency is almost water-like, allowing it to flow into small cracks, pores, and tight-fitting joints instead of sitting on top of the surface.
That makes it especially useful for aquascaping when two pieces of dry rock already fit together well.
For example, if two rocks have a solid contact point with only a small seam between them, General Bonding Super Glue can wick into that joint and reach areas that a thick gel may never penetrate.
The tradeoff is that it doesn’t fill gaps well. If there’s much space between the two surfaces, the glue can simply run through or away from the area you’re trying to bond.
Best Uses
- Tight-fitting dry rock joints
- Small cracks and seams
- Porous surfaces
- Aquascaping joints that already have good contact
Probably Not the Best Choice For
- Fragging sessions
- Uneven surfaces
- Large gaps
- Situations where you need the glue to stay in one spot
Learn More: Bulk Reef Supply General Bonding Super Glue
Maxi-Cure Extra Thick
Despite the "Extra Thick" name on the bottle, Maxi-Cure sits in the middle of these three options.
It’s thicker than General Bonding Super Glue, but it still has enough flow to spread across a surface and work into small irregularities.
That balance makes Maxi-Cure a great general-purpose fragging glue.
Add some to a frag plug, press the coral into place, and the glue has enough body to help support the frag while the bond starts to form. It can also handle small gaps between surfaces without immediately running away.
If you only want to keep one type of cyanoacrylate around for typical reef tank use, this is a very practical place to start.
Best Uses
- General coral fragging
- Attaching coral to frag plugs
- Small gaps between surfaces
- Everyday reef aquarium use
- Jobs where you want some flow without using a thin glue
Learn More: Bulk Reef Supply Maxi-Cure Super Glue
BRS Extra Thick Gel
BRS Extra Thick Gel is the thickest option of the three.
Instead of quickly spreading across a surface, it tends to stay in a mound where you apply it. That makes a big difference when the two surfaces you’re trying to bond don’t fit together perfectly.
A common example is attaching a frag plug to live rock. The bottom of the plug may be relatively flat, but the rock usually isn’t. A thicker gel gives you more material between those surfaces, helping fill the irregular spaces and create a stronger contact point.
The same idea applies when mounting larger branching corals. The thicker glue can help support the coral while you position it and give the bond time to start forming.
Best Uses
- Attaching frag plugs to live rock
- Larger coral frags
- Uneven surfaces
- Filling larger gaps
- Underwater mounting
- Jobs where you need the glue to stay exactly where you put it
Learn More: Bulk Reef Supply Extra Thick Super Glue Gel
Using Super Glue Underwater
Cyanoacrylate can be used underwater, but there’s a small trick to getting a good bond.
Once the glue hits the water, a thin skin begins forming on the outside. Press or gently twist the frag through that outer skin so the surface reaches the uncured glue underneath.
Then hold the frag in position while the bond begins to set.
For underwater applications, the thicker consistency of BRS Extra Thick Gel makes it particularly useful because it’s less likely to run away from the area you’re trying to glue.
Tip: if you’re going to put the actual glue container underwater, use one of the smaller 20 g tubes.
Submerging a large plastic bottle and then releasing your grip can draw aquarium water back into the bottle. Once water gets inside, you can quickly ruin a large amount of glue.
Can You Use More Than One Type for Aquascaping?
You bet! In fact, different viscosities can complement each other when assembling your aquascape.
A thicker glue can help fill space and establish the main connection between two pieces of rock. A thin glue can then flow deeper into smaller seams and pores around that joint.
You don’t necessarily need to choose one glue for every job. Choosing the right consistency for each part of the project will make aquascaping easier.
What About Insta-Set?
If you’re working with cyanoacrylate on a regular basis, an accelerator like Insta-Set can also be useful.
Rather than waiting for the glue to cure on its own, Insta-Set dramatically speeds up the process and can take cure times from minutes down to seconds.
That can be especially handy during fragging or aquascaping when you don’t want to hold a coral or rock structure in position for an extended period of time.
Adam has been keeping reef aquariums since 2010 and has worked in the aquarium industry for much of his career. He began at Bulk Reef Supply in Customer Service, helping hobbyists troubleshoot problems and build more successful tanks. Today, he writes educational content and product descriptions that help reef keepers better understand saltwater aquariums and make confident decisions. He believes the best tanks are built around what you enjoy, not what’s trending.
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