Cleaning supplies -- you can get all these locally. TSP is usually in the paint section. Any clean plastic 5 - 10 gallon bucket with a lid will work for soaking:
Rubbermaid BRUTE Gray 10 Gal Container w/o Lid @ Amazon
Round Brute Lid For 10-Gallon Waste Containers, 16" Diameter, Gray
1lb Savogran 10621 Trisodium Phosphate (TSP) @ Amazon
Cartridge -- you need 2:
Unicel C-4607 Replacement Filter Cartridge (Easy Set Size A or C) @ Amazon
If you shop around on Amazon, be very careful. Most of the products that say "Unicel" somewhere in the description are NOT Unicel, but one of a variety of Asian made products, that are NOT equal in effectiveness.