Define requirements and constraints
Record the baseline and check purchase, energy and genuinely required replacements. 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 durability, access and maintenance time 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 three- or five-year cost for the chosen scenario before continuing. Keep a reference so the result can be compared. Test the assembly under controlled conditions and record settings that must be repeated.
Cheap equipment can cost more through energy or proprietary consumables.