The Caldera 31489 filter cartridge delivers 30 square feet of pleated filtration for cleaner, clearer spa water. It’s one of the most widely compatible cartridges in the Watkins family of spa brands, serving a broad range of models across decades of production — so it’s a dependable replacement to keep on hand.
Filtration is the quiet backbone of good spa water. Every soak leaves behind body oils, lotions, hair, and fine debris, and the cartridge is what removes all of it before it clouds the water, feeds bacteria, or coats your plumbing. When a filter is worn or clogged, the effects spread everywhere: dull water, higher chemical use, softer jets, and a pump and heater straining against restricted flow.
This is the compact 30 square foot size — roughly 6 inches across and 10-1/2 inches tall, with open ends top and bottom. Many spas that use this cartridge run more than one at a time, so the set works together to handle the full filtration load. Like all Caldera filters, it’s made in the USA.
Pro Tip: Check how many cartridges your spa uses before you order. Spas built around this 30 square foot size very often run a set of two or three rather than a single filter, and they should always be replaced together. Pairing one new cartridge with older ones leaves the fresh filter doing more than its share and gives you uneven filtration across the set.
Brand
Caldera®
