Housing Seal O-Ring for Aqua UV Ultima II Filters, 1,000 to 20,000 gal

This O-ring seals the primary housing connection point on mid-to-large Ultima II filters covering the 1,000 to 20,000 gal range. Nitrile rubber resists UV, ozone, and the chemical exposure typical of pond water, but it still hardens and loses compression over years of seasonal use. When the filter develops slow weeping at the housing joint, this OEM replacement O-ring typically resolves it.

Compatibility

Diagnosis and Replacement

A slow drip at the housing joint during normal operation or after backwash points to a compressed or cracked O-ring. Shut down the filter and drain the tank. Remove the bolts securing the housing, lift the top away, and inspect the O-ring groove. A darkened, hard, or visibly cracked O-ring needs replacement. Before seating the new O-ring, inspect the mating surface for scratches or gouges and smooth any rough spots. Apply a light coat of silicone grease to the new O-ring before pressing it into the groove.

Preventive Maintenance

Inspect this O-ring annually at spring startup and replace it every 5 to 8 years regardless of condition. Catching it before it fails prevents mid-season water loss and the pump work that goes with maintaining a low-level pond.

Ideal for Ultima II pond filter owners maintaining mid-to-large filter units in the 1,000 to 20,000 gal range.