Nyos Reef Cement How To & Review

Nyos REEF CEMENT is literally a cement that can be used in our reef tanks. Nyos state on the packaging that it is “not harmful to corals or fish, is “low in harmful substances” and “can be used to attach corals” to rockwork. This is very a different type of aquascaping product with some very specific advantages. On opening the container the dry powder looks and smells like cement. It mixes like cement too, but ‘goes off’ in about 2 minutes allowing you to work you rock-structures into nearly any shape you can imagine.


To mix the product you need approximately 3 parts cement and 1 part water. If you use less than this the dough-like ball sets before you can work with it and crumbles. If you use too much water you get a very wet mix, but despite being very wet, it will still set very quickly. We started mixing it in a plastic measuring cup but found that a blue party cup was easier to use for smaller batches. Using the blue party cup allows you to feel when the mix is starting to set, as it heats up really fast. Once you feel the heat, you have seconds to get it in place. I used a lot more than was really needed on this small rock-structure.

It’s easy to make a real mess with this stuff so make sure you use it in a ‘cement safe’ area.

The directions are to mix a dough-like ball and push into the joints as needed, much like you would with epoxy. And this works very well, but we found working with it when it’s a bit wetter was easier and created a nice natural looking joint. We even experimented with a maple-syrup consistency mix and poured it over the joint. This worked very well too and created a strong joint, but you lose the ability to push it around and texture it. Our preferred texture was something more than ‘buttery’, but not all the way to ‘play-dough’. You just have to hold the joint for a few seconds while it sets. You can see the finished results from these different mixes below.


The results were impressive. As expected from cement, the joint is extremely strong and feels ROCK solid. I can’t emphasize enough how strong it is. Much stronger than any epoxy rockscape i’ve ever worked with. It’s a slightly darker colour than the rock itself but doesn’t stand out as much as most epoxy’s. It blends in very well. The big win is the strength of this stuff over conventional 2-part epoxies when aquascaping your rocks. While it can be a bit messy to work with, the results make it well worth it, even for small projects.


For small frags and corals you may find a 2-part epoxy or super glue quicker to work with. However, Reef Cement would provide a much stronger bond and is ideal for top heavy or difficult to place corals. I wouldn’t think twice about placing a big hammer coral on a vertical rock wall with Reef Cement. The real advantages come when you’re building your rockscape. The natural look and rock solid strength of the joints are unmatched. Using Reef Cement can also eliminate the need for adding zip ties and acrylic rods to strengthen your rockscape. This is especially true for larger tanks or big rock structures. Reef Cement sets quickly and will hold larger rocks in place with rock like hardness.