Water and Filtration

Identify the actual filter components and their care requirements, distinguish routine service from genuine replacement, and preserve the aquarium's biological needs rather than making every part look new at once.

Understand why biological media is part of a working water-treatment system, distinguish visible circulation from demonstrated biological performance, and keep changes tied to the actual filter instructions.

Compare the installed position, service access and actual media arrangement of two freshwater filter designs, then check suitability for the complete aquarium instead of choosing from a category label alone.

Identify exactly what a test measures, follow its own sampling and reading procedure, and preserve units and uncertainty before using a result to make an aquarium-care decision.

Understand why biological filtration must become established, distinguish elapsed time from demonstrated readiness, and prepare a freshwater aquarium without using fish to test an unfinished system.