Hayward | W3S180T | ProSeries 18" Top-Mount w/ Valve

The Hayward W3S180T ProSeries 18" Top-Mount Sand Filter is a compact filtration system for above-ground and small in-ground pools. It pairs a corrosion-proof polymer tank with a 360-degree self-cleaning underdrain to deliver clear water with very little upkeep. The top-mount valve keeps the footprint small and puts every filter function within easy reach.

Key Features

• 18" tank diameter, sized for compact pool filtration needs
• Top-mount multiport valve for simple control and operation
• 360-degree self-cleaning underdrain for balanced flow and consistent performance
• Corrosion-proof, precision-molded polymer tank built to last
• Integral diffuser distributes water evenly across the sand bed
• Uses standard #20 silica sand, not included
• Large sand and water drain for quick servicing and winterizing
• Easy-to-read pressure gauge for accurate system monitoring
• Quiet, energy-efficient operation
• Suitable for above-ground and small in-ground pools

Specifications

• Brand: Hayward
• Model / Part Number: W3S180T
• UPC: 0610377386920
• Filter Type: Sand
• Tank Diameter: 18 inches
• Valve Configuration: Top mount, multiport
• Tank Material: Corrosion-proof molded polymer
• Media Required: #20 silica sand, sold separately
• Best For: Above-ground and small in-ground pools

Frequently Asked Questions

What size pool is the Hayward W3S180T good for?

The 18-inch tank makes it a match for above-ground pools and smaller in-ground pools. Larger pools are better served by the 21-inch, 24-inch or 27-inch ProSeries models, which offer more filtration area and longer runs between backwashes.

Does the W3S180T come with sand?

No. Filter sand is sold separately. The filter uses standard #20 silica sand, which is the common grade carried by most pool supply stores.

What is the difference between top mount and side mount?

On a top-mount filter the multiport valve sits on top of the tank, which keeps the overall footprint narrower and is generally simpler to plumb. Side-mount filters put the valve beside the tank, which can make the valve easier to reach but takes more room. The W3S180T is a top-mount unit.

What does the self-cleaning underdrain actually do?

The 360-degree underdrain spreads water evenly through the full sand bed rather than channeling through one path. That means more of the sand does filtering work, backwashing clears debris more completely, and pressure stays lower for longer.

How often should I backwash this filter?

The usual guidance is to backwash when the pressure gauge reads roughly 8 to 10 PSI above your clean starting pressure. Note your clean reading after a fresh backwash so you have a baseline to compare against.

Do I need a specific pump to run it?

Match the filter to your pump's flow rate rather than to horsepower alone. An oversized pump can push water through the sand too quickly for effective filtration. If you are unsure, check your pump's flow curve or ask us before ordering.

Is a valve included?

Yes. This listing is the filter supplied with its top-mount multiport valve, so you are not buying the valve separately.

Can I use this filter on a saltwater pool?

Yes. The tank is molded polymer rather than metal, so salt water does not corrode it. Normal water chemistry maintenance still applies.