When using any kind of aquarium equipment that doses chemicals to your water, it’s best to use systems with multiple redundancies. If a feed pump fails for one reason or another, it could possibly dump a huge amount of whatever product it was feeding, such as a kalkwasser solution or even just plain old freshwater. These obviously can wreak all sorts of havoc on a saltwater aquarium, but these accidents can be prevented. An example of a common mishap is the water level sensors or float valves tied to top-off setups. Snails, calcium, and all sorts of debris can prevent the top-off from operating properly, potentially causing a major headache and some wet carpet. To add a redundancy to this system, put it on a timer so that it can only run for a short amount of time. You could also add secondary float valves to give you even more peace of mind.