Selecting Your Aquarium Live Rock

As we know aquarium live rock is an extremely effective filtration media to use within the saltwater aquarium. Not only does it provide filtration it also makes the aquarium look more natural.

With so many different types of live rock available however which one should you choose and how much do you need.

When setting up your aquarium you should have an idea as to what you want to keep and also what you hope it to look like. During the planning stage you should have looked into the following as well as numerous other aspects :

  • Location
  • Aquarium size
  • Overflows (if required)
  • Stand design
  • Plumbing (if required)
  • Filtration basics
  • What you hope to keep
  • etc…

Of course there are various different types of primary filtration you can choose for your aquarium. It is up to you the aquarist to decide, however for the purpose of this post we will presume that [tag-tec]aquarium live rock[/tag-tec] is the filtration of choice.

The first thing that you need to work out is how much live rock you are actually going to need in relation to the amount of water in your aquarium. This is of course a hard aspect to work out as it does depend upon what you are keeping and how much ‘stock’ you will have in your aquarium – it is presumed that you will not be overstocking….

….of course you wont – good.

There is another variant when it comes to calculating the amount of [tag-tec]live rock[/tag-tec] which you will need in your aquarium and that is the type of live rock you will actually use. There are various types you can use. For more information you can see the post ‘Natural Aquarium Filtration’

For this example I will base the calculation upon fully cured [tag-tec]Fiji live rock[/tag-tec] as this is the most common one used.

The basic calculation to follow is that you will require 1 1/4 to 1 3/4 pounds per gallon of water in the entire aquarium system. When you are working out the gallonage of water remember to include the sump if you have opted to use one.

If you are unsure as to the water volume your aquarium holds then you can use a calculator which can be located here.

Now you should be in a position where you know how much water your aquarium hold before displacement and how much live rock you roughly need. If you are not completely sure about how much live rock you will need then purchase a bit more just to be safe.

Now comes the funs bit – purchasing it.

Again in this example I will base this post upon fully cured aquarium live rock.

There are effectively 2 ways you can purchase live rock – one is via mail order or the internet and the second is in person.

I personally prefer the latter option as you get to physically choose the pieces yourself. With this first option someone, somewhere will choose the pieces for you and you effectively get what is delivered. This does have benefits however which are normally down to cost. If you shop around in magazines and on the internet you can get a great deal.

The second option of choosing them yourself is more fun though but what do you look for?

When you visit the shop have a good look around the shop first to see what sort of condition their aquariums, fish and corals are in. This will give you a good estimate as to how the shop is run and how things are maintained. If you have already built a relationship with a local fish shop then this should not be a problem for you.

Have a good look at the live rock holding tanks and see what the pieces look like. If possible ask about their curing process and ask if you can see their curing vats. This is good as again you can see how they cure them and how much care is put into preserving the life on the rock. This is not always possible as some shops purchase live rock in fully cured.

When it comes to choosing your live rock you should have a rough idea as to what you hope your live rock structure(s) to look like. Bear this in mind when choosing the pieces. Have a good look at the pieces, ask for pieces to be removed for inspection if you can.

What you need to look for is that there is nothing decaying on the rock and especially that there are no pests present. This may take some looking for and you may have to be patient but it is worthwhile. Imagine how devestated you would be if you got your purchases home and a huge bristleworm for example poked out of the rock!

Look for good coralline growth on the rocks. This shows that the rock is of good quality and has come a good quality stock. You will probably not get a great deal of things appear from the rock after it is in your aquarium. You might get some but that is not why we purchase live rock is it, we purhcase it for it’s magnificent filtration capabilities not for what might grow. If anything does grow then this is a bonus.

Try and pick pieces which will help you build the structure you desire. You will never get pieces which are the exact fit, however you can do the best you cnan. It will make aquascaping a lot easier later on – trust me.

Once you have made your selections the shop employee should remove them and pack them into a suitable container. Normally they are wrapped in paper or something similar so that the rock can remain damp in transit. They are left damp so reduce any further die off whilst they are on the move between the shop and your aquarium. There will be some die off experienced, however if packed correctly this should be minimal.

You are now in a position to be able to take your aquarium live rock home and begin the fun bit…..


  1. Great article.
    Live rock is an essential modern reef where the Berlin Method is employed. It can also be crumbled and used in place of bio balls in wet/dry filters or prefilters for mud filter or refugiums. This filtration article deals with this:

  2. Hi Carlrs

    Thanks for the compliment – glad you enjoyed it.

    You are correct with your comments – live rock really is am amazing and powerful filtration medium.

    Good article by the way


  3. You have to buy it in person. Something like this you really need to check out with your own eyes rather than relying on descriptions. This article is helpful though, thanks John!

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