Can I use regular liquid or tablet detergent?

No, Tetra is designed to work exclusively with the SMART DOSE™ Detergent Cartridge System, a first-of-its-kind dosing and multi-chemistry cleaning cartridge system that delivers optimal amounts of prewash, enzymes, and spot removal based on each wash cycle selected. The cartridges will last for 20+ loads, and the system will alert you when there are five washes remaining so you can order replacements online.