Filter Accessories

Pool filters depend on their small parts to stay reliable. The tank is built tough and doesn't fail easily. The accessories are where the trouble usually starts: the multiport valve you use for backwashing, the O-rings sealing the lids and connections, the pressure gauge that spots trouble early, and the drain plug that quietly weeps until you notice the puddle. Get any one of those wrong and the whole filter suffers.

This page covers all of it, from a single O-ring to a full valve rebuild kit. Browse swimming pool filter accessories from Pentair, Praher, Waterway Plastics, Val-Pak, WATERCO, Vak Pak Builders, CMP, and Horizon.

Swimming Pool Filter Accessories

The category is wider than most people expect. It's not just valves. It's every component that connects, seals, monitors, controls, or supports the filter system. Here's how it breaks down.

Filter Control Valves

Multiport valves, top-mount and side-mount, are the most common valve type on sand and DE filters. A standard 6-position MPV lets you switch between filter, backwash, rinse, waste, recirculate, and closed, all from one handle. Side-mount pre-plumbed valves like the Praher SM2-PP3 come factory-fitted with union connections, which speeds up installation on new builds or straight swap-outs.

Control Valves

These aren't the same as multiport valves. Control valves, meaning ball valves, check valves, and diverter valves, manage flow direction throughout the circulation system, not just the filter's backwash cycle.

• A check valve prevents backflow from the filter line to the pump
• A diverter valve splits or redirects flow between two circuits
• A ball valve isolates equipment for service

If you're sorting out which does what, our guide to valve types breaks each one down. Source replacements by port size and connection type.

Seals, O-Rings, and Gaskets

Every pressurized connection on the filter relies on an O-ring or gasket to hold. The most commonly replaced ones are:

• The tank body O-ring, the large ring sealing the filter lid to the tank
• The valve-to-tank flange gasket or union O-ring
• The drain plug O-ring

Val-Pak and Praher both stock these as individual O-rings or as model-specific kits.

Pressure Gauges and Air Relief Valves

The pressure gauge is your filter's primary diagnostic tool. A clean filter typically reads 8 to 15 PSI at normal operating flow. When pressure climbs 8 to 10 PSI above your clean baseline, the filter needs servicing. A gauge reading zero with the pump running, or a needle that sticks, usually means the gauge itself has failed, not the filter.

The air relief valve sits at the top of the filter tank and bleeds trapped air before and after cleaning cycles. Pentair's High Flow Manual Air Relief Valve, part 98209800, is a widely used replacement on Clean & Clear Plus, FNS Plus, and SMBW 4000 Series filters. The kit includes the valve, pressure gauge, hose clamp, and O-rings in one assembly.

Equipment Parts & Hardware

Clamps, cover plates, washers, hose adapters, handle assemblies, and drain plugs with gaskets are the parts that get ignored until a service call turns into a 90-minute hunt for one component. CMP and Horizon stock both individual small parts and complete kits that cover common and harder-to-find configurations. Horizon's dial valve covers and bodies, including the DV6 and DVK7 series, and CKS push-turn caps all fall here.

Above Ground vs. In-Ground: Does It Matter for Filter Accessories?

For most above ground pool filter accessories, the differences come down to pipe size and connection type rather than category. Here's how the two compare.

In-ground filters, especially commercial and larger residential, run higher flow rates and pressures. Praher's TM-22-LA, for example, is a 2" bolt-down top-mount MPV for Waterco filters used in higher-volume in-ground applications. Larger commercial systems may also need manifolds to run tanks in parallel, or a separation tank to settle out spent DE for code-compliant discharge, both of which live under commercial filter control valves.

The bottom line: check the port size and connection style, whether clamp-on, bolt-down, or union, on your existing filter before ordering. The valve body dimensions and mounting pattern need to match your filter's inlet and outlet. There's no universal fit between 1.5" and 2" systems.

How to Match a Filter Accessory to Your Existing System?

This is where most buyers run into trouble. "Pool filter valve" on its own narrows nothing. The right part depends on your filter brand, model, port size, mounting style, and in some cases the year of manufacture. Getting the pool filter accessories parts right the first time comes down to reading two or three specs off your existing equipment.

Matching Multiport Valves by Connection Type and Port Size

Start with the filter label. It lists the manufacturer, model number, and usually the valve model if it's factory-fitted. The two key specs are:

• Port size: 1.5" or 2" are most common. Running the wrong size chokes flow or causes fitting problems.
• Mounting style: top-mount clamp-on, bolt-down, or side-mount pre-plumbed union. These are not interchangeable without modification.

Praher manufactures valves used by Pentair, Waterco, and others under OEM agreements. A valve labeled "Pentair" and one labeled "Praher" may be the same part in different packaging. Cross-referencing by part number is always the most reliable approach.

Finding the Right O-Ring or Gasket by Model Number

O-ring sizing uses a standard numbering convention, O-411, O-497, and so on, that maps to specific inside diameter and cross-section dimensions. That makes it straightforward to find the correct O-ring for a filter lid, union, or drain plug. If you don't have the part number, measure the old O-ring's inside diameter and cross-section with a caliper and match it to the nearest standard size.

When to Replace Common Filter Accessories?

Most pool filter accessories don't announce themselves when they fail. Here's what to watch for.

Gauge and Air Relief Failure Signs

A gauge that reads zero with the pump running, reads erratically, or has fogged or cracked glass isn't giving you reliable data, and bad pressure readings mean you won't know when the filter needs cleaning or when something's actually wrong. Gauges are almost always 1/4" NPT bottom or center-back mount and typically run about $15 to $30. Replace the air relief valve at the same time if it's stiff, won't fully seat, or is weeping around the threads.

O-Rings, Gaskets, and Clamps

O-rings degrade from UV exposure, pool chemicals, and heat cycling. Visible cracking, flattening, or any weeping around a filter lid or valve connection means the O-ring has given up. Catch it early, at the first drip, and you avoid water loss and potential equipment damage. Replace with a silicone-lubricated EPDM O-ring of matching dimensions.

Clamp bands and plastic clamp assemblies should be inspected annually, especially on above ground setups where the filter may be moved during winterization. Cracks in the clamp band or stripped knobs are a pressure safety issue, not a cosmetic one. Pool filters operate under sustained pressure, and a failed clamp can let the tank lid separate suddenly and forcefully.

Swimming Pool Filter Accessories Brands in This Catalog and What They Cover

Ordering in Bulk or Stocking Up for the Season

Pool service companies and contractors stocking up before the season opens can request a volume discount quote directly through DK Hardware. Pricing adjusts on quantity, and orders ship from the US warehouse closest to you, which keeps lead times short even during peak spring demand when everyone needs parts at once.

Returns are accepted within 30 days on stocked items, and the support team is available 24/7 if you need to confirm compatibility before placing an order.

Frequently Asked Questions - Pool Filter Accessories

How do I know which multiport valve fits my filter?

Check the filter label for the brand, model number, port size (1.5" or 2"), and mounting style (top-mount or side-mount). Those three specs together determine the correct valve. If the label is gone, measure the tank opening diameter and inlet pipe size.

My filter is leaking around the multiport valve. What's causing it?

It depends where the leak is. Water around the lid means a failed cover O-ring. Water from the backwash port while in filter mode means a worn spider gasket. Water around the handle stem means failed stem O-rings. In most cases a key assembly rebuild kit fixes all three without replacing the whole valve.

What's the difference between a spider gasket and a tank body O-ring?

The spider gasket sits inside the multiport valve and directs water to the correct port. When it fails, water leaks out the backwash line in filter mode. The tank body O-ring seals the filter lid to the tank. When it fails, you get an external drip at that joint. They're separate parts and not interchangeable.

Can I use any lubricant on pool filter O-rings?

Only silicone-based lubricant. Petroleum-based products, including Vaseline, degrade EPDM rubber over time, causing swelling and cracking. A thin silicone coat every time you open a pressurized connection is all it takes.

My pressure gauge reads zero with the pump running. Is the filter blocked?

A blocked filter shows high pressure, not zero. A zero reading usually means the gauge itself has failed, there's an air leak at the pump losing prime, or a downstream valve is closed. Replace the gauge first, since they run $15 to $25 and are the most common culprit.

How often should I replace pool filter O-rings?

Go by condition, not a fixed schedule. Any time you open a pressurized connection, inspect the O-ring. If it's flattened, cracked, or weeping, replace it. With proper silicone lubrication, a quality EPDM O-ring can last several seasons.

What's the difference between a top-mount and side-mount multiport valve?

Top-mount valves sit directly on top of the filter tank and clamp or bolt at the tank flange. Side-mount valves connect to the side of the tank via union fittings. They mount completely differently and are not interchangeable, so always match the mounting style of the original.

How do I find the right replacement O-ring without a part number?

Measure the old O-ring's inside diameter and cross-section with a caliper, then match to the standard AS568 sizing chart. Val-Pak and Praher both publish cross-reference charts by filter brand and model, which is the fastest path if you know your filter make and model.

Get the Exact Filter Part Before Your Next Service Call

The filter tank rarely fails. The parts around it do, and having the right one on hand is the difference between a five-minute fix and a callback. Match your port size, mounting style, and O-ring dimensions off the existing equipment, then order the exact pool filter accessories parts you need from the eight brands above. If you're not sure a valve or gasket matches your filter, the DK Hardware team can cross-reference it by part number before anything ships, and volume buyers can lock in season pricing on the same call.