Calculate TDH during off season

I have a 18,000 gal saltwater in ground pool with 2 returns, 1 skimmer, and 2 drains in deep end (right next to each other). Pump is about 15 feet from deep end with a foot between suction pipe height and water level. I’m thinking my pump is oversized for the pool because the circulation is strong in the pool and the water level drops several inches when I backwash. Current system has a 2 hp super pump and a filter that is rated for 62 GPM. Is there a way to make a good guess for TDH when the pool is close to purchase the new pump before I open the pool?

Hello Olafkett - Below is a couple sources you can use to calculate feet of head.

How Do I Calculate Feet of Head for My Pool

How to Measure Total Dynamic Head with Gauges

Head Loss Calculator

Do you think my pump is oversized based on what I described?

It’s oversized unless there are other water features that we don’t know about. This would include a spa, waterfalls, solar panels or anything else that requires more flow.

That’s all the features of the pool. Would you say the pump is excessively oversized? I’ve had a pool store recommend a 1 1/2 hp pump for the pool but the only reason they gave me was that since it’s an inground pool of that size it needs that size pump. Anything less than that would be undersized. I feel if I were to drain the pool using the pump, it would be completely drained in about 1 to 2 hours based on the amount of water I lose when I backwash.

I’d say the pump is excessively oversized. I would recommend something like the Pureline Prime model PL2605. It’s a 1.65HP variable speed pump. It will definitely have enough power for your vacuuming and backwashing. You could run the PL2605 on a low speed to circulate the pool the rest of the time. This would be a huge energy saver and a better way to filter the water.

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