Guide 07: Aquariums & Water Absorption — The Hidden Dielectric RF Sponge

Water possesses a very high dielectric constant (approx. 80 at room temperature) and high dipole relaxation characteristics at microwave frequencies. A standard 50-gallon home fish tank placed between your router and your workstation acts as an impenetrable liquid sponge for 2.4 GHz and 5 GHz signals.

The Molecular Physics of Liquid Attenuation

Electromagnetic waves cause polarized water molecules to rotate and absorb energy as thermal friction. A mere 5 centimeters of water can attenuate a 5GHz Wi-Fi signal by more than 20 dB. An entire aquarium block will completely obliterate packet reception for devices behind it.

Rule of Thumb: Never position a router directly behind, beneath, or adjacent to aquariums, decorative indoor fountains, or large water heaters.