Wanting to stack rocks in your aquarium, but afraid of a landslide in the future? Well, there are plenty of options for securing that tower of rock, and many of them are readily available at your local fish store or even hardware store. A popular choice is reef safe epoxy, which is usually a two part putty that remains somewhat flexible, but is a bit messy at times and doesn’t always do the trick. Another choice is zip ties, but those are only good for a limited number of things and often flex or break over time. Some hobbyists drill their rocks and put in either PVC piping or acrylic rods, which is a great way to stack the rocks really high. And finally, there are cement-like products that work really well at bonding two or more pieces of rock together…with the best part being a really good blending of the two pieces so they almost look like one. Having tried most of these, we like to go with a mixed bag approach. We’ve found that a combination of acrylic rods and either the epoxy or the cement work really well, especially in the long term. Zip ties are so so, and the holes for the PVC have to be way too large for our liking. But, there are lots of options out there making the rock structure an easier task than ever.