Description
This filter set is the exact replacement required for the 2025 MasterSpas Challenger 21 D and Trainer 21 D swim spas. Each R4 cartridge, built with a 2‑inch female pipe thread connector, is designed to house the EcoPur® Charge Mineral Cartridge inside. The four MA40 cartridges install alongside the R4s to complete the filtration system, delivering the full water clarity and purification balance your swim spa was engineered for.
Includes:
- 2 × Master Clear MA‑R4 Filters (2" FPT) – Primary cartridges designed to capture dirt, debris, and particles.
- 2 × EcoPur® Charge Mineral Cartridges – Fit inside the R4s for mineral purification.
- 4 × Master Clear MA‑40 Filters (2" FPT) – Cartridges that work with the R4s to deliver full system performance.
Important Fit Notes:
- ✅ Fits 2025+ Challenger 21 D
- ✅ Fits 2025+ Trainer 21 D
- ❌ Not compatible with other Trainer or Challenger models outside these specifications
- ❌ Not compatible with older swim spas using the R4 (1.5" MPT) bundles
🗓️ Replacement Schedule
- Filters: Replace every 12 months with regular care, or every 6 months with heavier use
- EcoPur® cartridges (inside the R4s): Replace every 6 months
Please verify your swim spa’s model and production year before purchase. Due to the nature of the product, we cannot accept returns on opened or incorrectly ordered filter sets.
