New pump recommendations from you old Pros


Aug 30, 2016
Mid Missouri
Hey all!

I am looking to replace my pump this year before opening and am looking for some expert recommendations.
Last fall I had noted the old one was getting very old and it was a little scaled and grinding a lot and did not seem to be performing as well, so I wanted to replace it before it goes out in dramatic fashion mid season causing a green monster requiring a more expensive emergency last minute swap. Also have to buy a new 6 way valve that cracked due to old sun damage as well but from what I have seen that is just a need to swap with OEM from company of filter.

I have read the pump schools and hydraulics heads but was more more curious to so overall preference from an experience standpoint of how much pump my simple system and filter can handle to get the most flow and turnover possible without overpowering or damaging it.

Any recommendations with the following in mind? Cost, flowrate, quality, dependability/life expectancy, efficiency, noise

My pool Specs:

24 foot diameter 48 inch tall Silverlake Doughboy AG pool in Missouri climate

[13,500 gal Running through skimmer/ 16,500 to top​]

Old pump Pentair Dynamo II N1 1.5HP 340210 pump with switch , powered via grounded GFCI outlet to waterproof extension not direct wire as pump will be brought indoors for winter.

Filter Cristal Flo II Sand Filter 19 inch diameter
Filter Area 1.92 Sq. Ft., 150# Sand Required (75zeosand), 35 Max. Working Pressure, 40 Design Flow Rate GPM.

Running 1.5" flexible hose above ground short runs and 30ft vacuum hose.

**and PS on a TFP note,
I peeled back the cover and whipped out my TF-100 to test the water after a full neglected winter to find beautiful crystal clear sparkling water still balanced with 14.5 free chlorine and pH 7.6.



TFP Expert
Apr 29, 2016
Quaker Hill, CT
Great to hear that your water is still clear after the long winter.

Take a second and Edit your signature so its easier for us to see what equipment you have on your pool.

You've got a pretty simple set up there. The only thing I would recommend for you to change would be to go to a 2-speed pump to save on the utility bills. A 1hp 2 speed pump dynamo pump should be a direct fit replacement for the pump you have now. You would only need to take the cord off the pump you have now and wire it to the new pump. The pump curve for the 1.5 hp and 1 hp dynamo pump is exactly the same so on high speed it will basically be the same pump as you have now. On low speed which is where you should be running it 99% of the time it will be super quiet and flow plenty of water for your pool. The only time you would really need the high speed would be for backwashing and vacuuming.

A new valve head for your filter is easy to get just double check the part numbers on the valve you have to get the right version of the valve.


Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
Sebring, Florida
The 40 gpm flow rate for your filter is a little too small. You should not go to a pump that will exceed that.....your current pump probably already does.

A 1HP 2-speed would be my suggestion unless you decide to change the filter for a 60-80 gpm new one.


Aug 30, 2016
Mid Missouri
Yeah, I made a sig when I first signed up here but I was on biguanide back then and deleted it when it trashed the pool and I ended up with the full conversion as if it changed my equiptment lol.

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