Our Hakko HK-D 25 diaphragm rebuild kits are quick and EASY TO INSTALL. All you need is a phillips screwdriver and a medium pair of pliers. If you find yourself replacing Diaphragms on your air pump more than once a year you may need to evaluate your air line tubing and air diffusers. Excessive back pressure in the design of your aeration system could be the problem. Cleaning your air diffusers is an important maintenance procedure for longevity of your air pump. Feel free to call our headquarters for help determining if your air system is set up efficiently.