# Live Rock, Coraline Algae and Filtering



## gus1911 (Feb 2, 2008)

When live rock becomes encrusted with coraline algae and the porosity of the rock is no more, how does the rock continue filtering the water? Isn't the microlife now dead? After encrustation, what's the benefit?


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## onefish2fish (Jul 22, 2008)

you shouldnt need to worry about a coraline takeover. it prob. wont be that dense covering everything, atleast not for a good period of time and even then you will be fine. id would guess just from someone saying their tank is covered in such a dense coraline that it has matured for some time. if anything if it does happen enjoy it as it is a pretty algae, i have/had it in a few different colors growing in my tank. as long as your alk, ca and mag are in check you shouldnt have a hard time getting coraline. you could always take scrapings to "seed" your tank but usually just throwing some live rock in a tank with good water parameters you should have it growing regardless. assuming you have a reef, corals will grow on the live rock too. the critters should still be present and a nice size refugium is always good.


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## Pasfur (Mar 29, 2008)

gus1911 said:


> When live rock becomes encrusted with coraline algae and the porosity of the rock is no more, how does the rock continue filtering the water? Isn't the microlife now dead? After encrustation, what's the benefit?


The primary benefit of coraline algae is to deter unwanted algae growth. Systems with good coraline growth have less risk of hair and bubble algaes, and generally experience more rapid coral growth. Coraline is an ideal surface for corals to to lay down a base an spread, exactly the opposite reaction that corals have when they encounter hair algae.

Coraline is also an indicator of the overall health of your system.


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## gus1911 (Feb 2, 2008)

I have a "live rock" in my reef that I suspect is not "live" at all. I bought it because it was covered top to bottom with coaraline algae. I see that's good, but that rock is not doing any filtering, right?


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