What size sand filter for 1 1/2 HP pump?

Jun 7, 2010
6
I'm replacing the cartridge filter with a sand filter. The guy at the pool store says I need this huge 30" Hayward 500 lbs. sand filter because he says the 1 1/2 HP pump I am using now is too big for a 24" 300lbs. sand filter. What do you guys think? The pool is kidney shaped 20x30 ft. at widest part.
 
How about a little more background ... like did you just buy a new pump? why? what size pump did you have before? What model is the new pump? Why do you want to change filters? What is the new filter model number? What is the volume of your pool?
 
jblizzle said:
How about a little more background ... like did you just buy a new pump? why? what size pump did you have before? What model is the new pump? Why do you want to change filters? What is the new filter model number? What is the volume of your pool?

Not replacing the pump. This is an old bronze pump that still works great. Replacing cartridge filter because way to much work cleaning all the time. Here in Houston have many trees and pollen that clogs too much. Want sand filter that we can back-wash. I want to replace with Hayward S244T 24" 300lbs sand filter. Pool store guy says my 1 1/2 hp pump is too powerful for that filter and said I needed the Hayward S310T2 Pro-Series 30-Inch Filter with 500 lbs sand. I guesstimate the pool holds 22K to 24K gallons. I noticed on Amazon that when you look at the 24" filter that it says frequently bough together with the Hayward 1 1/2 HP pump. I can't find on the Hayward site any reccommendations on pump sizes.
 
Well, first based on your pool size, we would recommend a 4.2+ sqft sand filter. This equates to a ~28" size. So the 24" (3.14 sqft) is actually quite a bit smaller than we would recommend, independent of the pump size. And given your mention of a lot of debris, I would suggest you go with a larger filter or you will find yourself unhappy with the sand filter due to having to backwash fairly often.

With the 30" filter, you will likely have to backwash pretty rarely, and then there is certainly no concern about the pump size. Really the only time pump size would come into play would be if you have a very large pump and a very small filter. The 24" would function with the 1.5 HP pump, although it would have a higher head loss and thus higher pressure and because the water flow rate would be faster than the 30" through the sand, it may not filter quite as well.

I too would think you would be happier with the 30" (although nothing to do with the pump size) and then in the future seriously consider a smaller 2-speed pump (assuming you have no need to high flow rates, like spa, waterfalls, etc) to same money on electricity.
 
You will NEVER regret going with a larger filter. I would make the move to the #500 filter in a heartbeat.

My large pool has a #950 lb. filter (1.5 HP pump) and it has been about the best "extra" money I have spent
 
I promise you that my 22" 250 lb. sand filter is, in my opinion.."over-driven" by my 1.5 hp pump. I.E.-----it doesn't catch as much fine stuff as it should as the flow rate is too high. Bigger is better on sand filters. I even put in a Hayward C-225 cartridge filter inline after the filter end of last summer and you wouldn't believe how much pollen and fine stuff it catches.
 
This is a follow up on the 30" Hayward filter I purchased.
The pool is now sparkling blue with so much less effort then the cartrige filter I had. I couldn't be happier with the purchase. To be able to vacum to waste and clean the filter so easily by just back- flushing! WOW!
Thanks again everyone for the great advice!
 
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