If a piece of acrylic equipment on your marine aquarium cracks or breaks, it’s not necessarily the end of the world. The bodies on protein skimmers and reactor products crack all of the time, and random plastic parts break off with such frequency that hobbyists have just come to expect it to some extent. When these items crack, and it’s a crack that’s more than aesthetic, the broken equipment can be salvaged with a bit of Weld On, or some other plastic solvent. If the crack is fine, it’s best to use the really runny solvent. If the crack is larger, the thicker stuff would work far better. In any way, the item can be repaired back to a somewhat normal operating condition.