Aladdin Tank O-Ring PF50, O-185-9

The Aladdin O-185-9 is a replacement tank o-ring for Pentair PacFab PF50 pool filters. It is approximately 30 inches in diameter and 3/8 inch thick, and it may fit other filter models built on the same tank.

What it does

A side mount filter tank is made in two halves held together by a clamp band, and this ring is the seal on that split. It is the largest o-ring on the filter and the one that gets disturbed every time the tank is opened for a grid or media service.

Fitting it

Seat the ring fully in its groove all the way around before the top half goes back on, and use a silicone based o-ring lubricant so it does not roll or pinch as the clamp is drawn up. Petroleum grease attacks the rubber and should not be used. A pinched tank ring will not seal at pressure no matter how tight the clamp is.

Cross references

The same ring appears under the numbers 152038, O-185, 4600-2038 and 90-423-1185, which is useful if you are matching against an old parts list.