1/3 HP vs 1/2 HP pump: 1/3 HP is the minimum, 1/2 HP if you want to sleep through the night

A 1/3 HP pump rated for at least 2,000 GPH handles most pools, but a 1/2 HP is worth the extra $30–40 for huge covers (over 20x40) or tropical downpours. The tiny 1/6 HP or 1/4 HP pumps will struggle and burn out. Don’t trust “heavy duty” labels—check the GPH at your actual head height, and always get an automatic pump with a float switch.