- Hi, I'm Wayland from Marine Depot.
Today we're gonna talk about
one of the most foundational components
of a reef aquarium, live rock.
(cheerful whistling guitar music)
When reef keeping first began,
traditional saltwater aquarists were confused
by the term live rock.
How could rock be living?
But once they saw a reef aquarium
where the rocks were bursting with marine life
like corals, encrusting algae and sponges,
it was clear that reef rock played a key role in reef tanks.
At first we thought rock was just a structure
to place corals,
and a space for shrimp and crabs to explore.
But over the years, aquarists and marine biologists found
that most of the life associated
with reef rock was microscopic.
The rough surface of live rock and the microscopic pores
created by reef-boring algae and fungi
are home to an invisible jungle of marine microorganisms
that work behind the scenes to maintain a reef ecosystem.
A recent discovery showed that coralline algae
are the preferred landing spot for coral larvae.
That's not new.
But what is new is that certain corals
prefer specific species of coralline algae.
But there's more.
Each species of coralline algae
has its own unique bacterial biofilm.
The bacteria releases a chemical called TBP.
The coral senses the chemical,
and knows if it's a right algae to settle on.
The coral will only attach to the rock
if they receive the proper signal about the coralline algae.
For reef aquarists, live rock provides a solid surface
for the formation of biofilms.
Biofilms are communities of cells stuck together
by a polymer slime.
The polymer provides protection against UV exposure,
changes in salinity,
natural antimicrobial compounds, and predation.
The biofilm is not a single layer.
A mature reef tank has layer upon layer
of living biofilm on the rock.
Nitrifying bacteria convert ammonia to nitrite,
and then from nitrite to nitrate.
Denitrifying bacteria will remove the nitrate
by converting nitrate to nitrogen gas.
Other microbes work to recycle a variety of nutrients
and organic matter.
A teaspoon of seawater contains
about five million bacterial cells.
Lab studies reveal
that there are up to 400 times more bacteria growing
on a solid surface than in seawater.
And then there's algae, fungi, and protozoans
that live on top of the biofilm.
Live rock is home base for this microscopic zoo.
You can see that much of the biological filtration
in the reef aquarium takes place on the rock.
Live rock also provides ledges and crevices to place corals
and develop a life-like reef aquarium.
All natural reef rock harvested from the ocean.
Before Fiji rock was banned from export,
Fiji rock was the most common type of live rock.
It was relatively lightweight and easy to handle.
Fiji rock is usually boat-shipped,
which can take up to 30 days to arrive
at the supplier's warehouse or fish store.
Much of the marine life on the rock
will not survive that long journey.
Air shipments are possible for this live rock,
but very expensive.
Tonga Branch is a denser, heavier rock.
The antler-like shape adds an interesting dimension
to the layout, and it's best used as accent pieces.
Pukani rock is from Fiji,
but it's lighter and quite porous.
It's available in larger pieces, and it's usually stacked
to create stable shelves for corals.
Man-made rock harvested from the ocean.
Aquacultured live rock starts
as either pieces of calcium rock or man-made rubble.
It is scattered in the ocean, and left for several years.
Over that time, the rock becomes colonized
with marine life, and looks like natural live rock.
Aquacultured live rock is sustainable,
and does not harm the reef ecosystem.
It usually comes from the Gulf of Mexico or the Atlantic.
That means, if you live in North America,
it arrives fresh, and in good condition.
All live rock must be inspected
for decay and dead marine life.
The farther it traveled,
the greater chances is will need to be cured, here's why.
Dead bacteria, sponges, worms,
and algae start to decay during shipment.
If you place the rock directly into your tank
after shipment, chances are very good
that the decaying marine life will release harmful ammonia,
phosphate, and organics into your water.
Curing live rock and dry live rock.
Cure lightly if it's good live rock.
Cure heavily if there are chances of pests
or a lot of decay.
If restarting a tank, heavily cure infested live rock.
Use a soft brush to remove any dead surface material.
Poke around in the crevices with a thin pick or a pencil
to dislodge any crabs or worms or any other hitchhikers.
The ideal curing method is to place a live rock
in a plastic trash can or a tub filled with saltwater.
Heat the water to about 78 degrees fahrenheit,
and add a submersible pump for water movement.
If the rock has a lot of decaying material,
it can take several weeks,
or even months until it's flushed from the rock.
If the water smells bad, or has high ammonia,
you know it's gonna take a while to cure.
Some aquarists make a water change every week
to remove the excess ammonia and decaying organics.
If you choose to cure your rock in your aquarium,
you will need to make a 100% water change
after the cure is complete.
And chances are, your water will be yellow
and full of algae-promoting nutrients.
Many aquarists will say they wish to cure their rock
in a plastic tub instead of the aquarium,
and that's our recommendation as well.
There's a downside to starting a reef tank with live rock.
No matter how careful you are with the curing process,
undesirable hitchhiking marine life
will find their way into your tank.
Fireworms, bubble algae, and aiptasia are common pests
that sneak into the live rock.
Another option is dry rock.
This is dried live rock from the ocean.
Even though it's completely dry,
it still will leach nutrients and organics
as the dead marine life on the rock decays in your water.
It should be cured just like live rock.
So check the water for ammonia and odors
during the curing process.
There are exceptions.
AquaMaxx dry rock is an all-natural, dried reef rock
mined in the state of Florida.
AquaMaxx rock needs no curing,
since it doesn't contain any living or dead organisms.
All that's needed is a quick rinse, and it's ready to use.
Using mined rock, like AquaMaxx
or CaribSea South Sea Base Rock
eliminates the curing process, and also prevents hitchhikers
and it gets your reef up and going very quickly.
It will take time for the bare rock to become coated
with coral and algae and biofilm,
but over time, it will mature,
and will look great in the aquarium.
CaribSea's Life Rock is dried reef rock
with a purple coating that looks like coral and algae.
Over time, living coral and algae will cover the rock
as the tank matures.
Of all the questions we receive about reef rock,
surface area seems to be the number one concern.
Many aquarists get hung up about which rock is more porous,
or has the most surface area.
They're worried there won't be enough surface area
to support biological filtration.
The truth is, reef aquariums have very low bioload
compared to intensive aquaculture operations.
Surface area can be limiting, and fish grow all seasons,
but not in our home aquariums.
That's why we don't need wet-dry filters on reef aquariums.
It's important to understand
that the density of the microbial biofilter
matches the amount of ammonia, nitrate,
and organic nutrients produced in the tank.
More surface area doesn't automatically mean
a larger biological filter will form.
No matter which rock you use,
there will be more than enough surface area
for nitrification, denitrification, and nutrient recycling.
When the biofilm matures, it bursts,
sending out microbes to start a new colony.
This keeps the biofilter fresh and active at all times.
In fact, biofilms have a life cycle.
They don't stay in the same place on the rock.
It's in a constant state of breaking apart,
and starting new biofilms.
This brings up the next question.
How much rock do I need?
Well the answer is not related to surface area.
A lot depends on the design you're looking for.
Some like a tank packed with shelves.
Others like a single pile of rock in the center of the tank.
For the typical reef tank,
with rock piled along the back of the tank,
we recommend about one pound per gallon.
Extra rock can be broken up for rubble
or placed in a refugium.
If you're using dry rock, we recommend seeding the tank
with pieces of rubble from another tank or refugium.
You can also use a bacterial starter product.
The best way to get coral and algae started
is to scrape some from a piece of rock,
and disperse it into the new aquarium.
And also, many coral frags have a coating of coralline
that will also seed the rest of your aquarium.
The key to working with live rock is patience.
Part of the enjoyment of reef keeping
is watching the transformation of a bare tank
to a beautiful reef.
If you have to cure the rock, allow for plenty of time
to properly flush out the pores of decay.
If you go with dry rock, take your time,
and allow the rock to become live slowly.
Thank you for watching our video on live rock today.
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Until next time, let's build a better aquarium, together.