The best substrates to use for a refugium include live sand, live rock, live rock rubble, Marine Pure blocks, Miracle Mud, or just leaving the refugium bare bottom. ... Knowing your specific tank needs and having a goal for your refugium will make a substrate choice easier.

Should I put sand in refugium?

Depending on what you want to grow in the refugium. Certain macro or marine plants can be partial bury in the sand. If you don't planned on have those, then no need for sand. Likewise, LR and media is personal preferences in the refugium.

What should I put in my aquarium refugium?

Fish, snails, shrimp, corals, crabs, corals, and copepods can all be put in the refugium. Though all of these animals can live in the refugium doing so could impact the goals you may have for your refugium.