Hot Spring C30 Filter Cartridge fits the following Hot Spring Spas.

• Vista
• Aria
• Envoy
• Grandee
• Jetsetter
• Prodigy
• Propel
• Samoa
• Sovereign
• Square / SX 
• Hotspot R
• Stride
• Triangle
• Triumph
• Vanguard

Have you tried the Tri-x Filter? These fit all pools with a C30 filter currently but have a long life (5-8 years) and are Dishwasher safe!