Live Rock (Part 1): The Benefits & Types of Live Rock

If you are just entering the reefing world or researching it because you’re planning to, you may not realize an essential component of any reef tank is the “live rock.” This plays a critical role in the long-term health and maintenance of any tank.

What is Live Rock & What Does It Do for Your Reef?

Live rock can be a confusing term for beginners. The rock itself is not technically alive; however, the marine organism and bacteria that live on and within the rock’s pores are alive. These organisms and bacteria play a crucial role in maintaining a healthy reef tank.

Types of Rock

There are several different types of rock. It is essential to choose the right kind of rock during the initial set-up phase as changing out the rock in an established tank is difficult. The type of rock will impact the tank’s look and how long it will take to cycle.

Dry Rock

Dry rock refers to different types of live rock that are dried out completely. Dry-rock is an environmentally friendly option commonly harvested (i.e., dug up) from ancient reef systems no longer underwater. Dry rock is usually the most affordable. However, it generally takes longer to cure and can take 3-6 months or longer for good purple Coralline algae coverage. To speed up the curing process and growth of Coralline algae, add a piece of previously cured live rock with coralline algae to the dry rock.

  • Average Cost: $3-5 per lb 
  • Average Curing Time: 1-2 Months
  • Eco-friendly: Yes, as long as it is not from existing coral reefs.
  • Example: Marco Rocks

Aquacultured Dry Rock

Aquacultured Live Rock is created by placing a dry rock into the ocean for an extended period. Like a dry rock, it is an environmentally friendly option. It has many of the same attributes as live rock harvested from a reef and generally needs a short curing time.

  • Average Cost: $6-8 per lb
  • Average Curing Time: Less than 1 Month
  • Eco-friendly: Yes, as long as the original dry rock is not from existing coral reefs.
  • Example: Florida Aquacultured Live Rock

Artificial Rock

Artificial rock refers to human-made or synthetic rock made from the same mineral building blocks as live rock. And because it is not taken directly from the oceans, it is sustainable and eco-friendly. Artificial rock is generally free of hitchhikers, organics, or algae.

  • Average Cost: $6-8 per lb
  • Average Curing Time: Less than 1 Month
  • Eco-friendly: Yes
  • Example: Real Reef Rock

Live Rock

Live rock from Fiji, Tonga, the Marshall Islands, and other locations used to dominate the trade; however, due to the environmental impact to live coral reefs, this type of rock is no longer available.

  • Average Cost: No longer available
  • Average Curing Time: Less than 1 Month
  • Eco-friendly: No
  • Example: None

Shapes & Sizes Of Live Rock

Live rock can come in many different shapes and sizes. Before purchasing, create an aquascaping plan and determine what shapes and sizes you will need.

Foundation or Base Rock

Medium to large-sized chunks of rock that are heavy, dense, and porous. The porous structure allows for the growth of beneficial bacteria, and the larger size creates a stable foundation for aquascaping.

Table or Shelf Rock

Lightweight, flat, and porous. Shelf rock creates aquascaping depth and is an ideal location for coral placement.

Arch, Branch, and Decorative Rock

Arch, branch and decorative pieces add depth and help create a more realistic-looking reef.

The Difference Between Cured & Uncured

Most reef shops will store live rock in their systems, so it is usually partially cured. However, it is never a bad idea to ask questions before purchasing. Before purchasing, find out where the rock came from and how it’s cared for before sale.

Uncured Rock

Uncured rock means there is dead and decaying matter inside the rock due to letting rock dry out, shipping, improper storage, or other causes. An uncured rock usually has a foul smell.

Cured Rock

Cured rock means the bacteria and organisms in the rock are alive and healthy. With the proper temperature and water parameters, rock is kept live without being in the main display.

If you are unsure if your rock is uncured or cured, place it in a bucket or other container with salt water for 24 hours and then test for ammonia. If ammonia levels are unsafe, cure the rock before adding it to an existing tank.

Buying Tips for Live Rock

Variety is best when purchasing rock for a reef. Varying degrees of porousness, density, and sizes ensure you have sufficient conditions for beneficial bacteria to thrive, stability in your aquascaping and safe places and crevices to plant coral.

Have a question? Need supplies for your aquarium? Give us a shout here or visit our store locator to check our products today. Happy Reefing!

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