Pump selection for small pool

[mvoltin]

I am building a small 8,000 gallon pool with around 17GPM (2x8h turnover) requirement for the pump. Feet of head is minimal (5-6' for either main drain and skimmer) and have large cartridge filter and plan on salt chlorination So, my filter needs to be really small. Unfortunately, I cannot figure out how small it has to be since most articles i read walk you through the entire process except of the last step (translating to the pump HP) except this one article that shows in step 8 that 1/2 HP pump should give around 45GPM with 30 feet of head.

1. Can you help me point to a right place to figure out exact size for my pump at 17GPM and under 30 feet of head requirement? Even if I reduce the turnover time to 4 hours, my flow rate is still 34GPM but would rather have a longer turnover.
2. Assuming I need 1/2 HP or weaker pump, can you recommend one? I have hard time finding anything this small for in ground pool - most start at 3/4HP and up.
3. My in-ground pool has a pit right next to it that allows me to put pump and all the equipment at the pool bottom level. If I cannot find the appropriately small pump among in-ground selection, can I use small above-ground pump instead since I do not need self-priming? I have read a lot about this but the responses are usually "above-ground pump is made differently and it is not recommended for in ground pool" (even when the self-priming is not an issue.) without going into any specific explanation. Can someone help me understand better why this is not an option, what is different beyond self-priming feature?

thank you so much,
Mike,

 

[cowboycasey]

welcome to TFP Mike

Small or larger pool I would go bigger is better.. below is what I have and it works, my spa is only 700 gallons and I have a 100 sq ft filter on it and my pool has a 420 sq ft filter for 15000 gallons.. the bigger filter allows you to go longer without cleaning, so a 420 filter you would only need to clean once a year You say you have a large cartridge filter, what size is it?

pump: I love my 1hp pentair, on low 90% of the time and uses very little power and when you need extra power to vacuum or clean its there on high... and the price is great..

Amazon.com : Pentair 340042 SuperFlo High Performance Energy Efficient Two Speed Pool Pump, 1 Horsepower, 230 Volt, 1 Phase - Energy Star Certified : Swimming Pool Water Pumps : Patio, Lawn Garden

this one is 3/4 HP 2 speed and plugs in
Amazon.com : Energy Efficient 2 Speed Pump for In-Ground Swimming Pool 0.75 HP-115V : Patio, Lawn Garden

 

[domct203]

IMHO a 1/2HP will be to small for the job, especially if you want to vacuum.

Is there a space limitation?

Dom

 

[mvoltin]

Thank you, Casey,

the first options looks like something I will go with. it will allow me to run on low speed for general filtration and then at a higher speed to run few jets (built-in spa connected to the pool - same level, etc.). I still have to go to the basement to see the filter model and will post it soon.

Mike

P.S. the second pump was little harder to research - could not even find a website and another customer (from Amazon Q&A) said that the pump failed in couple of months and could not find anybody that would provide a warranty.

 

[mvoltin]

Hi Dom,
Space is not really a huge issue but almost every pool recommendation/guide i have read overemphasizes the importance of calculating actual requirements and not over-sizing the pump. I just wanted to do it right and based on my calculations of less than 17GPM, I assumed I needed something less than 1/2hp (assuming the chart from this article is correct and 1/2HP pump provides around 45GPM).