Types and Qualities of Live Rock

There are many ways to classify Live Rock... or in other words, there are many different criteria that can be used to describe Live Rock, to categorize it, and to describe its qualities. Unfortunately, the most commonly used criteria are not the most helpful at describing how "good" (or bad) Live Rock is from the point of view of its capacity to deliver the benefits previously outlined.

In the next paragraphs we outline some of the main criteria use to describe Live Rock, the different types of rock within each criteria, and the different qualities associated with each type of rock.

Origin

This refers to where was the Live Rock harvested from?

This is probably the most commonly use criterion used to describe Live Rock. So for example, Fiji Live Rock means that the rock was harvested somewhere in the coast of the Republic of Fiji Islands... and Tonga Live Rock was harvested somewhere in the Kindom of Tonga.

Most of these cool-sounding names are actually names of countries and islands... and since most of us have no idea where in the map they are located, we decided to add some on the map below as a reference... just hover your mouse over the bubble-markers to pop-up a name tag.

Sources of Live Rock


Although origin may be the most used criterion to describe and classify Live Rock, it actually gives little information on the capacity of the rock to deliver benefits for your aquarium.

When considering wild-harvested Live rock, as a rule of thumb, a "new" origin name in the market may start by referring to very impressive rock because it may be from a newly exploited harvesting location that contains "old-growth" and a selection of sizes and shapes... After a while however, the pretty stuff starts running out and "uglier" stuff makes it to the market... then prices start to go down, which means that it is time to move to another location... hence another "new" name comes out.

On the other hand, origin could roughly tell you what species of algae and hitchhikers you could expect on your rock. However we want to emphasize the word roughly, because there is a large variability between reefs of an area. Fiji rock from one reef could look completely different that Fiji rock from another reef just a bit deeper than the first one... however Fiji rock from either reef would have very different organisms compared to Live Rock from the Caribbean Sea.

Subjective assessment of aesthetic appearance

This refers to how "good-looking" is the Live Rock?

The aesthetic assessment is normally done by the manger of a retail or online store, and is based on the shape, degree of coralline algae cover, and amount and diversity of cryptic organisms (i.e. hitchhikers).

The assessment is subjective and most often the categories are set by dividing the available rocks into tiers. For example... the "ugliest" 50% of rocks only modestly covered with algae may be called Fiji rock, while the next 40% may called Fiji premium and only the best-looking 10% is classified as Fiji ultra-premium cherry-picked.

When comparing "quality" of rock from one given supplier or retail store (say premium vs ultra-premium), probably most people would concur that there is an aesthetic difference (that is ultra-premium is nicer than premium). HOWEVER, comparing "qualities" from different suppliers may be ambiguous and could mislead customers. It is completely possible that premium rock from supplier A is way nicer looking that the ultra-premium rock of supplier B.

Tip: Ask for up-to-date photos and, if possible, buy a sample.

Curing state

Rock in the ocean is in equilibrium with ocean conditions and it has to be allowed to re-equilibrate to tank conditions. The process is called "curing".

Live rock can be Cured, Uncured and pre-cured.... more soon.


Shape

  1. Branch


Size

This classification differentiates Nano Live Rock from other types of rock. Nano Live Rock are selected for their small and are picked having in mind small (nano) tanks.

Production technique

  1. Wild-harvested
  2. Aquacultured
    1. Ocean-aquacultured
    2. Tank-aquacultured


Rubble species

This refers to the species of stony coral that produced the rubble forming the non-living matrix of the Live Rock.


Substrate used (only for aquacultured rock)

  1. Mined limestone
  2. Concrete calcareous-media aggregates

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