Onga Sta-Rite Tank O-Ring (P21/P25) – 702223 / SR35505-1358

Genuine Onga Sta-Rite Tank O-Ring for the P21 and P25 sand filters — SKU 702223, old part number SR35505-1358. This large rubber O-ring seals the multiport valve to the sand filter tank body. A worn or cracked tank O-ring causes water to leak from the joint between the valve and the tank. Replacing this O-ring restores a watertight seal and maintains correct system pressure.

Compatibility

• Onga Pantera P21 sand filter — multiport valve to tank connection
• Onga Pantera P25 sand filter — multiport valve to tank connection
• Sta-Rite multiport valves
• Onga Pantera multiport valves

Product Details

• Brand: Onga (Pentair)
• SKU: 702223
• Old part number: SR35505-1358
• Barcode: 698343
• Material: rubber
• Genuine Onga spare part

Frequently Asked Questions

How do I know if this O-ring needs replacing?

If water is leaking from the joint between the multiport valve and the top of the sand filter tank on your Onga P21 or P25, the tank O-ring is the most likely cause. Turn off the pump and relieve system pressure, then remove the multiport valve and inspect the O-ring for cracks, flattening, or deformation. Replace if any damage is visible.

What is the difference between part numbers 702223 and SR35505-1358?

Both numbers refer to the same O-ring. 702223 is the current Onga/Pentair part number. SR35505-1358 is the older Sta-Rite part number used in earlier documentation and some supplier catalogues. Either number can be used to identify this part.

Should I lubricate the O-ring when fitting it?

Yes — apply a small amount of silicone-based O-ring lubricant (not petroleum-based grease) to the O-ring before fitting. This helps the O-ring seat correctly, prevents pinching during assembly, and extends its service life.