A reef aquarium or reef tank is a marine aquarium that prominently displays live corals and other marine invertebrates as well as fish that play a role in maintaining the tropical coral reef environment.
A refugium or fuge is a remote location that provide an isolated environment, separate from the main aquarium for the cultivation of macroalgae, live foods a...

A reef tank refugium provides an isolated environment, separate from the main aquarium, for the cultivation of macroalgae, live foods and biological denitrification.

Moving forward, it's essential to keep these visual contexts in mind when discussing Reef Aquarium Refugium And Water Hardness.
Refugiums are small tanks added to a reef aquarium that are used to grow micro-fauna and macro-algae that feed the livestock and help consume excess nutrients that nuisance algae use to grow. They can be easily installed in a sump or hung on the side of the aquarium.

Different reef tanks will have different needs and individual reef keepers will have different goals with their refugium so one size best substrate choice probably doesnt fit, but knowing the options can help you dial in a best-fit decision.Complete Guide to Reef Aquarium Water Parameters.
Reef Tank Dimensions. Reef Aquarium Display Refugium.Designed to fit inside the aquarium cabinets of 90cm, 100cm and 120cm aquariums, the sump includes a water top up bay that is perfect when used in...