What glue is best for aquarium use?

Cyanoacrylate-based glue, also sometimes called "Super Glue" or "Crazy Glue", and you want to get the gel. The gel form is just easier to manage, especially underwater. It is reef safe, cures underwater, and adheres well to rocks and frags.

There is a wide selection of super glue out there and the main difference is going to be the thickness of the gel.  While some glues are quite watery, it is best to find a thick gel for use in a reef tank.

How do I glue my corals?

Gluing frags outside of the aquarium is easy.  Just add a dime-size dab of glue onto your coral plug or rubble rock, dry off the end of the coral frag you want to glue, then hold it in place on the frag mount until it sticks on its own. It can take up to 90 seconds for the coral to stick on its own so just be sure you hold it long enough. 

**Pro Tip: Try to minimize the contact points with the coral tissue. Your fingers are often softer or gentler on the coral tissue directly but forceps can sometimes be ideal because of the smaller points of contact. Ultimately, the main goal is to minimize the damage to coral tissue on that frag. With too much handling of a coral frag, you can damage the tissue beyond the point of reasonable repair. When holding the frag, think of it as support moreover pressure. 

How do I glue my corals underwater?

Gluing underwater is a little trickier.  Holding the container of glue underwater, eject a small ball or bubble of glue into your fingertips. Gently roll the ball of glue onto the area of the rock you're gluing without breaking the skin of the "glueball". Push the coral into the ball of glue and hold it into place until it sticks on its own. The trick here is not breaking the skin of the glue with your hands, rather letting the coral frag itself pierce that skin and stick into place.  Then just be sure to hold the frag long enough to stick on its own. 

It is safe to say if your having trouble getting the frags to stick or stand on their own, 99% of the time you are either not holding it long enough or not getting that frag through the skin of the glue where it comes in contact with the uncured cyanoacrylate.

What is the cheapest glue per ounce?

The best-priced glue is the BRS Extra Thick in the 10oz container. The Jurrassic Gel is another favorite because of its thickness, even thicker than the BRS Extra Thick.

**Pro-Tip: Metal containers of glue, like the Jurrasic Gel or BRS 10g Extra Thick Glue, are important if you plan to use the glue underwater. Plastic containers like the BRS 10oz container will create suction and draw water back into the glue if you try to use it underwater as described above.  This moisture inside the container of glue will cause the glue to harden and cure right away.

Some hobbyists just stick with the small, single-use size glue, like the Polyp-Lab Premium Glue, which eliminates the risk of glue going bad during storage. We generally only recommend the larger containers of glue for situations like building an aquascape or when you're making more than just a handful of coral frags at one time.