Hayward Sand Filter with Top Mount Valve 16" Tank - W3S166T



Part # W3S166T

By Hayward Pool Products

  5 Average  



Part # W3S166T

Warranty 1 Year

Alternate Part #'s HAYW3S166T

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:
1.40 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.

?     Asked on 6/22/2021by Tim Floyd

I currently have a Hayward S166TW sand filter for my spa. What is the replacement part number? I understand it is obsolete.

A  Answered on 6/22/2021 by InyoPools Product Specialist Craig C.

Hello Tim.  The Hayward Products Sand Filter with Top Mount Valve 16" Tank model W3S166T is a compatible replacement for the Hayward S166TW.

?     Asked on 5/3/2021by Don

15 x 30 oval pool 48depth approx 11000 gallons. What size filter pump should I go with 1.0 with W3S166 or 1.5 with W3S180

A  Answered on 5/3/2021 by InyoPools Product Specialist Patrick P.

Hi Don, For your sized pool we would suggest the W3S180T93S Hayward Sand Filter System

?     Asked on 5/25/2020by Doreen

What size sandfilter for a 21x52 pool?

A  Answered on 11/3/2020 by InyoPools Product Specialist Hector F.

Hi Doreen, for your size swimming pool I would suggest a sand filter in the range of 18-22 inches. 

?     Asked on 4/12/2020by Dustin DuMond

I am putting a 12.5x7 foot plunge pool (in-ground). Will this filter work for my size of pool? Also what pump do you recommend?

A  Answered on 11/19/2020 by InyoPools Product Specialist Megan C.

We will need the total gallons to properly size the filter. If this pool has an average depth of 5.0' the approximate total gallons is 3,281. The Sand Filter with Top Mount Valve 16" Tank - W3S166T is ideal for the total gallons, it can filter 14,400 gallons in 8-hours and has a max flow rate of 30-gallons per minute provided by the pump. If you selected this filter you will need a pump that does not exceed 30-gallons per minute at 50' of head (industry standard is 50' of head,* all pools vary for feet of head design). Please see How to Size a Pool Pump for Your In-Ground Pool and How To Size a Pool Filter before ordering (click on the highlighted descriptions to view the hot to guides.  

?     Asked on 6/29/2018by Inyo Visitor

when would you use the recirculate function on this filter

A  Answered on 6/30/2018 by InyoPools Product Specialist Lennox H.

Hi, When you need to bypass the filter due to broken lateral, ineffective filtration etc.  

?     Asked on 5/22/2018by Sharon

I have a 26 x 52 intex pool and want a sand filter what kind and size do you recommend?

A  Answered on 5/23/2018 by InyoPools Product Specialist Patrick P.

Hi Sharon, This would be a good filter for an Intex pool. You may need to purchase some additional Intex Adapters to connect this filter to your pool. If you are looking for a complete pump and filter system then I would suggest something like the PureLine 19" Sand Filter with 1.5 HP Pump.

?     Asked on 5/20/2018by Sharon

When replacing sand in my Hayward S166T, my husband got sand in the lateral assembly center pipe. We removed as much as we could after adding 100 pounds of sand. Will this be a problem and what should we do eliminate this sand from entering our pool.

A  Answered on 5/21/2018 by InyoPools Product Specialist Lennox H.

Hi, Sharon. You will need to remove all of the sand from the standpipe. This will allow you to get sand into your pool. You can vacuum the sand out of the pool once it settles. 

?     Asked on 2/1/2018by Inyo Visitor

My above ground pool came with a Hayward S166T sand filter. this says for an inground pool. Is it the ssame filter. The seam cracked in my filter and is leaking so I assume it needs replaced. Thanks

A  Answered on 2/2/2018 by InyoPools Product Specialist Lennox H.

Hi. This Hayward Sand Filter - S166T can be used with both above and in-ground pools. This filter can be used as a replacement. 

?     Asked on 11/6/2017by Tim

I have a 1 1/2 hp hayward power flo pump and a 18' round 52" deep pool. my 22" sandman filter is bad. can i replace it with a s166t 16" filter ?

A  Answered on 11/7/2017 by InyoPools Product Specialist Lennox H.

Hi, Tim. A 16" Sand filter is too small for a 1.5 HP Powerflo pump. I would recommend a 22" or larger sand filter. 

?     Asked on 6/15/2017by Inyo Visitor

I own A 18' round , 48" deep. Would the 16" filter tank be good to use, and does all the internal parts come with the filter ? what size pump is recommended with the 16"?

A  Answered on 6/15/2017 by InyoPools Product Specialist Patrick P.

Hi, yes this filter would work on an 18' round 48" deep pool and it does come with all of the internals. You will need a pump and I really like the PureLine 19" Sand Filter with 1 HP Pump this is a really great system.

?     Asked on 6/5/2017by Julie

I have a new pool that is 12X20 oval. My old pool was larger (17X24) I want to use my old filter which is a Hayward S166T90 Pro series and 1.5 horsepower pump. Is this filter and pump ok to use with the old filtration system? Also, will I still need to run the filter for 8 hours?

A  Answered on 6/11/2017 by InyoPools Product Specialist Patrick P.

Hi Julie, Your old Hayward S166T90 Pro series and 1.5 horsepower pump would be fine for your 12 x 20 Oval Pool. We would suggest running the pump 8 hours per day.

?     Asked on 5/24/2017by mc

what s good sand filter for 18000 in ground oval with one end being 48 in deep and 1 end is 72 in deep

A  Answered on 5/25/2017 by InyoPools Product Specialist Scott W.

That is going to depend on your flow rate. What is your pump model and horsepower, and what is the distance from your pump to your skimmers so I can calculate that for you and recommend a suitable sand filter for you?

?     Asked on 11/9/2016by PATRICIA A DENOVCHEK

I have a 15 x 30 oval above ground pool 52" high. what size filter do I need?

A  Answered on 11/10/2016 by InyoPools Product Specialist Scott W.

The S166T is only going to be able to handle a flow rate of 30 gallons per minute and with an above ground pool there is not much resistance for the pump so the flow rate for the pump is usually higher than 30. It is going to depend greatly on the size of your pump. If you can give me the horsepower I can calculate the flow rate so I can recommend the correct size filter.

?     Asked on 7/4/2016by brian

is this 16in top mount valve good for an above ground pool

A  Answered on 7/8/2016 by InyoPools Product Specialist Lennox H.

Hi Brian, This 16" Hayward Sand filter is adequate for an above ground pool up to 14,400 gallons with a run time of 8 hours.

?     Asked on 7/2/2016by brian

I have a 9000 gal above ground pool I have a 1.5 horse power pump what kind of filter do I need

A  Answered on 7/3/2016 by InyoPools Product Specialist Alex V.

Brian, Based on the pool and pump size, I would recommend an 18" tank like the S180T.

?     Asked on 5/19/2016by Stacey

Would you recommend the 16" tank for a 24 ft above ground pool?

A  Answered on 5/19/2016 by InyoPools Product Specialist Alex V.

Stacey, Thank you for your question. I would recommend a Hayward S180T 18" sand filter tank for a 24' round pool.

?     Asked on 7/5/2015by Jim

Can I use this with my Hdayward Power Flo LX pump (1.5 HP) SP1515Z1BC

A  Answered on 7/7/2015 by InyoPools Product Specialist Lennox H.

Hi Jim, I would recommend the 18" Tank Top Mount Valve Sand Filter (S180T) or the 20" Tank Top Mount Valve Sand Filter to use with your 1.5 HP Hayward Power Flo LX Pump.

?     Asked on 6/26/2015by Rose

Can I use this filter for my Kayak 10,000 gallon above ground pool?

A  Answered on 6/28/2015 by InyoPools Product Specialist Lennox H.

Hi Rose, The Top Mount Valve 16" Tank Sand Filter can be used on your Kayak 10,000 pool only if your pump does not exceed 1hp.

?     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.

?     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 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 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 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.


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