This is a quote from a Ron Shimek article you may find inspiring ?
"Upon examination of the material of a coral reef it becomes apparent that corals are only one component of the life on such a reef, and although they appear large and evident, their contribution to the actual amount of living material on the reef is relatively small.
In their pioneering study of the reef at Enewetak atoll, the Odums in 1955 showed that the majority of non-bacterial biomass on a "coral" reef was actually in the form of algae. They found that various types of algae were everywhere. There were algae growing in the coral tissues, of course, as zooxanthellae, but additionally there were algae growing freely and widely across the coral reef. The algae on the surface of the reef were diverse in form, and belonged to many groups, from large green algae such as Codium, to coralline red algae, to coralline green algae, to diatoms and dinoflagellates. In point of fact, they found enough algae on the reef to consider it far more reasonable to call such reefs algal reefs instead of coral reefs. I wonder how many aquarists would be hobbyists today if these biogenic structures were named after their most abundant life forms and called "algal reefs" rather than coral reefs.
In addition to the algae growing visibly on the surface of the rocks, the Odums were surprised to find that algae were growing INSIDE of all the substrates on a reef. Algae, primarily filamentous green algae, lived inside of coral heads, inside of dead coral skeleton, and inside of all coral rock and rubble. In fact, on an old coral atoll such as Enewetak where all evidence of the volcano that gave the reef its start has vanished with subsidence (the volcanic basis for the reef at Enewetak is found under some 5,000 feet (1515 m) of coral reef deposited over several million of years coral growth), virtually all of the rocks are riddled with algae and contain a lot of algal growth and biomass.
The Odums found that in the average coral head, in the region of the polyps, the density of the algal component was about 0.004 grams/cm3 and the animal component was about 0.021 g/cm3, while among the bases of the polyps the filamentous algae had a density of about 0.022 g/cm3. Below the polyp zone of the coral head the algae had a density of 0.037 g/cm3. In other words, in a coral head with living coral tissue on it, the animal component accounted for about one-fourth of the total, 0.021 g/cm3, while the various algal components amounted for 0.063 g/cm3. Interestingly, as well, the filamentous algal component of a coral head had a much greater biomass (about 16 times greater) than did the zooxanthellae in the coral.
The algae in the coral heads do not die when the coral animal does, and the amount of the coral algae in various rock components of the reef is shown in Figure 1. This figure, modified from the Odums' 1955 paper, shows the relative biomass of several rocky areas on the reef. I have colored the algal biomass amounts green, and the biomass inside rock that could be collected as live rock in yellow. The amount of algae living inside the various components of coral rubble and rock is quite significant, and those algae are quite important to our discussion of live rock porosity. If corals are grown in environments free of the algae that colonize their skeletons, those skeletons are typically quite porous. However, the algae growing within the rock add to the porosity by dissolving fine holes for their filaments."
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http://reefkeeping.com/issues/2004-05/rs/feature/index.php
