What size pool pump should I use.
Key point: Choose the correct size pump bigger is not better.
When your pool was built your pool builder would have correctly sized the pump for your pool. If no equipment has been changed since pool was built the pump will be the right size. Unfortunately this is not always the case so you will need to check what size pool pump you have and compare it to what size would generally be used for that pool.
Most people think you select your poor pump size according to how much water is in the pool this is not the full story.
You actually need to size your pump to the filter that is being used in the pool and this is far more important for the following reasons.
1 A pump that is too large for a sand filter will not filter properly, the water passes across the sand with too much velocity and actually creates vertical channels in the sand bed, the high-speed water passes down these channels and does not get filtered by the sand.
2. A pump that is too large for a sand filter will also cause there to be too much pressure on the tank of the sand filter this can cause premature failure of the tank and laterals, the extra backpressure will also cause premature failure of the pump.
3. A pump that is too small for a sand filter will not backwash properly meaning the sand will not be lifted and cleaned once a month as it should be. The sand then becomes partially blocked and the system runs under too much pressure causing problems.
4. A pump that is too small for a sand filter can also result in a pool with low water turnover and dead zones in the pool which is often observed as algae in the corners or steps, if the pool has a salt chlorinator cell may not fill with water and the chlorinator will then turn automatically off and stop making chlorine.
5. Similarly cartridge filters will be under too much pressure if the pump is too large and the tank will fail prematurely. The cartridge element itself will also fail prematurely.
6. A pump that is too small for a cartridge filter is not as big an issue except for insufficient turnover of pool water and if it is a saltwater pool this cell may not filled with water properly and stop producing chlorine.
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