Pumps - General questions

• In the last few days, I have seen bubbles in my pump prefilter: why and what should I do?

• I need to change my pump, is it a good idea to get a more powerful one ?

• My pump no longer starts up and makes an electric groaning noise, what should I do ?

• I have noticed a water leak under my pump, what should I do?

• Which pool pump should I choose?

• How do I calculate the flow rate required for a pool pump?

• How do I choose the appropriate power for a pool pump?

• How can I calculate the power required for a pool filtration pump?