Define requirements and constraints
Record the baseline and check swimming space, refuges and broken sight lines. Do not infer the aquarium's condition from a single sign. Measure the real space, identify connections and preserve clearance for cooling and service.
Then compare the path from intake to return around structures with livestock needs and recent changes. Compare useful capacity, energy and compatibility with the complete setup.
Install for future maintenance
Adjust one variable and assess access for siphoning and animal recovery before continuing. Keep a reference so the result can be compared. Test the assembly under controlled conditions and record settings that must be repeated.
Secure rock and wood before filling because digging livestock can undermine them.