Hey folks - I've got mixed bed, color indicating DI resin for sale, as well as the refillable cartridges: $10 for the cart, $12 for the resin. Reduced price of $18 for a filled cartridge.
Also:
1 micron, 10" sediment filters - $2.75
1 micron, 10" carbon block filters - $9
Hanna Instruments...