Bilge pumps are cheap and very effective for quickly removing a large volume of bilge water. Kind of like an Arnold Schwarzenegger solution to a very small problem, as the vast majority of boats pocket very small amounts of water at several different locations. Whether it’s a rubber lobe, a centrifugal or a diaphragm bilge pump, they all have a couple of things in common: They pump water, but are not designed to move air with the water. So, their efficiency drops dramatically, once air touches the pump. Obviously, they are not able to remove all of the water, therefore, the average pump will leave about one inch of water behind, when it cycles off. This is how they are designed and there is nothing wrong with your bilge pump, so don’t complain that there’s some water left as the bilge pump manufacturers will tell you that this is normal. The general rule seems to be that the larger the pump, the faster the flow, but this results in higher levels of residual bilge water. The smaller the pump, the slower the flow, with generally less residual water. Bilge pumps are best described as a safety product because they are able to maintain vessel trim and floatation, in the event of a failure that allows water to flood into your bilges. Every boat needs at least one operational pump on board before leaving the dock.
The Arid Bilge System, on the other hand, removes water slower than a traditional bilge pump. It is correctly designed and sized for the average daily bilge water that finds its way into the vessel.