The PAR type pump also comes in bilge pump models. First People are always complaining about the unreliability of these pumps due to their history of frequent breakdowns. In fact, these pumps are reliable when installed properly, but frequently they are not. There are three main problems that usually cause their demise. They are located in a place that gets wet.
Diaphragm pumps are intolerant of any kind of debris in the water being pumped.
Freezing as a result of inadequate winter layup. Note that just replacing a water damaged pump isn't going to solve the problem. You need to eliminate the reason why it got wet. The second problem is one that can be solved by installing the appropriate sized strainer or filter so as to prevent debris from getting into the inner workings of the pump. Aluminum tanks will build up very heavy corrosion deposits on the inside of the tank.