External vs. Submersible Pumps. Which one should you Use For many people, it's never been a question of whether to use a submersible pump vs. an external pump because most people have smaller ponds and are used to just using a submersible pump. They're easy to install, and are pretty reliable - so why even consider an external pump?There are a couple of reasons...But before we go into that, let's briefly talk about the benefits of submersible pumps first. For obvious reasons, a submersible pump is named as such because it is designed to be placed in the pond, and submerged under the water. These are the easiest of all pumps to install, just drop them in the water and plug them in - and you�re ready to do. Of course, you might have some quick plumbing to do, attaching a hose to the waterfall or to a submersible filter (another article entirely), but other than that - that's pretty much all there is to it.Submersible pumps range in size or gallons per hour, from 50 GPH all th ... Read more »