Aquarium equipment guides

Sourced spec explainers for the equipment most beginners actually buy. No "best heater 2026" listicles — just the math, the spec hierarchy, and the failure modes worth knowing about before you spend money.

• Heater buying guide

  Wattage math, submersible vs in-line, accuracy specs, and the failure modes manufacturers don't put on the box. Includes the redundancy logic for tanks above 75 gallons.

• Filter buying guide

  GPH math, HOB vs canister vs sponge, why the box rating overstates real flow, and maintenance behaviors (rinse-in-tank-water, no-cartridge-only HOBs).