By Hayward Pool Products



Part # W3S166T

Warranty 1 Year

Alternate Part #'s HAYW3S166T, HPPW3S166T

Product Description

Inyo Recommended Filters


Hayward sand filters are the very latest in pool filter technology. Molded of durable, corrosion-proof polymeric material, they feature attractive, unitized tank construction for years of trouble-free operation with only minimal care. Pro Series sets a new standard for performance, value and dependability. 


  • In-ground pools of all types and sizes
  • In-ground spas--(residential or commercial)
  • Water features--(fish ponds, fountains, water gardens)


  • Flange clamp design allows 360 degree rotation of valve to simplify plumbing
  • Integral top diffuser ensures even distribution of water over the top of the sand media bed. Full-size internal piping provides smooth, free-flowing performance
  • Unitized, corrosion-proof filter tank molded of rugged, colorfast polymeric material for dependable, all-weather performance
  • 6-position Hayward Vari-Flo control valve with easy-to-use lever-action handle lets you dial any of the 6 valve/filter functions. Integral sight glass lets you see when backwash cycle is completed
  • Efficient, multi-lateral underdrain assembly, with 360 degree slotted, self-cleaning laterals, gives totally balanced flow and backwashing
  • Integral molded drain plug for easy draining of tank, without the loss of sand 

 Click here for more Hayward Filters

Product Specifications

Plumbing Size:
1 1/2 in.
100 lbs.
Flow Rating:
30 GPM
Filtration Area:
1.4 sq. ft.
Valve Location:
Valve Type:
Turnover 8 Hrs.:
14400 gal.
Turnover 10 Hrs.:
18000 gal.
16-1/2 in.
33 in.
Sand Required:
100 lbs.
Filter Type:
Pool Type:
In Ground

?     Asked on 1/27/2012by Guest

When should I change the sand in my filter?

A  Answered on 1/27/2012 by InyoPools Product Specialist Patrick P.

You should change the sand in your filter every 5-7 years. You can generally tell that it is time if your pool water is not as clear as it normally is or when you notice the interval between backwashes is shorter. You can use > this guide to walk you through it.

?     Asked on 3/1/2012by Guest

How often do I have to replace the sand in my filter? What is normal operating pressure?

A  Answered on 3/1/2012 by InyoPools Product Specialist Patrick P.

On a "fresh start-up" a filter would operate anywhere between 10-20 psi. As a general rule of thumb you only want to backwash when the pressure increases 8-10 psi. You want to make certain that the pump is being turned off whenever you move the handle on the valve. Once backwashing is complete (3-5 minutes), you can switch to the rinse option to re-settle the sand bed. Sand will typically last 5-7 years. Premature backwashing will wear down the size of the sand which will cause difficulties such as cloudy water and higher operating pressures.

?     Asked on 5/27/2015by Fred

For model S166T What size Pump would I need.? 1HP or would 1.5HP give me more filtration.

A  Answered on 5/27/2015 by InyoPools Product Specialist Patrick P.

Hi Fred for the S166T filter I would suggest not going larger than 1 HP. If you wanted to go with a 1-1/2 HP pump then I would suggest the Hayward S180T Sand Filter.

?     Asked on 5/31/2015by Dawn

Are the sand filters shipped with sand?

A  Answered on 5/31/2015 by InyoPools Product Specialist Patrick P.

Hi Dawn, No the sand filters are not shipped with sand, normally you can find pool filter sand at your local hardware store for around $5 per 50 lb. bag.

?     Asked on 6/24/2015by terri

I am trying to clear up a green pool, it started okay turned blue but cloudy. Everything was operating fine until i swept it? I did not realize i should have had it on waste to sweep and now there is no water going back into the pool? What did I do and what can I do to make it work again? Thanks!

A  Answered on 6/24/2015 by InyoPools Product Specialist Hector F.

Your filter is getting backed up with the dead algae that you have killed. You will need to remove all of the dead algae from the pool for it to clear up. One way is by backwashing multiple times a day or vacuuming the pool to waste. You can do this by placing the multiport valve into the waste position before manually vacuuming the pool which will discharge most of the dead algae that has settled on the pool floor. Keep the pool chlorinated, algae killed and filter as clean as possible until the pool has cleared.


Review Summary

 (Average 5  out of 5 stars)
3 Rating
5 star:
4 star:
3 star:
2 star:
1 star:

The Most Recent Reviews