Good question. And one that’s easily answered!

A diaphragm is the engine of your disc-based pool cleaner. It is important that this is not stretched or torn, as this will prevent your pool cleaner from working.

A diaphragm is also the most ordered pool cleaner spare part. Why? It’s the most used and abused part of your pool cleaner. That’s because the diaphragm is what creates the suction and release action in your pool cleaner. It works very much like a heart valve. It builds pressure, then releases it, builds pressure, releases it, and so on.

So, you can see why it takes so much strain!

Diaphragms come in distinct designs. They are, amongst others, a cassette-type, with a flat edge, and standard-type diaphragm, with a slanted edge.

These diaphragms are designed to function with specific types of suction pool cleaners so make sure to check your existing diaphragm, to make sure you’re ordering the correct one next time!

You should replace your pool cleaner diaphragm when you spot visible tears.