Category Archives: Rock

Live Rock – What Type is Best for Your Aquarium?

Live rock is the foundation of a saltwater aquarium. It plays a vital role in keeping your water clean and your aquarium healthy. It provides protection and shelter for your fish and critters. And it gives coral, sponges, and many other things a surface to grow on.

live rock with coraline
Live rock with coraline algae starting to grow on it.

There are several types of live rock to choose from. Let’s take a look at the advantages and disadvantages of some of the more popular options.

Pukani live rock:

Pros:

  • Very light weight and very porous. Pukani rock provides a lot of surface area for both aerobic and anaerobic bacteria. This means it is very good at helping to remove ammonia, nitrites, and nitrates from the tank.

Cons:

  • Most dry rocks that came from the ocean have high phosphates. However, many aquarists report Pukinai dry rock has more phosphate than any other type of live rock. High phospates can feed severe outbreaks of nuisance algae.

Tonga live rock:

Pros:

  • Comes in several unique shapes including branches and shelves.
  • Fairly light weight and porous.

Cons:

  • Like any dry rock that originally came from the ocean, it can have high levels of phosphate which may cause algae blooms as it leaches out of the rock into your tank water over the first 6-12 months of use.

Man-made live rock:

Pros:

  • Eco-friendly. You know for certain it is not being harvested from living reefs.
  • Low to no phosphates.
  • Comes in different shapes such as branches and shelves.

Cons:

  • Less porous than natural pukani or tonga rock.
  • Can be much pricier than other types of rock.

Florida Reef Rock:

Florida reef live rock is limestone rock that is quarried inland from deposits made up of what used to be ancient ocean reefs.

Pros:

  • Eco-friendly. You know for certain it is not being harvested from living reefs.
  • Florida reef rock from respected sources such as ReefCleaners.org and Marco Rocks are reported to have lower phosphates than most any other type of live rock.
  • Least expensive type of rock.

Cons:

  • More dense, heavier, and often less porous than Pukani or Tonga rock. So you need to buy a bit more to get the same amount of surface area and biological filtration the other rocks provide.
  • This means more cost, and more weight in your aquarium.
  • If it also lacks very fine pores there will be nowhere for anaerobic bacteria to grow. So, while it may help process ammonia and nitrate, it will not be very effective at reducing nitrates … so some other means of nitrate removal will be needed.

Each type of live rock can be purchased from numerous sources whether it be online or at your local fish store.

And they can be purchased in different ‘states’.

By this I mean you can get pieces that are literally dry chunks of rock (old coral skeletons to be exact) that will need to be cycled and cured.

You can get pieces that have already been cured, cycled, and are shipped or bought wet. This means they are ready to use and have little or no other life on them other than the bacteria needed to consume the harmful ammonia, nitrites, and nitrates produced as waste by the fish and critters in your aquarium.

Or you can get pieces that are aqua-cultured and teaming with life. This means they not only have the need bacteria to act as a biological filter for your aquarium. They will also be covered in anything from barnacles and sponges to coral and crabs.

Each of these ‘states’ of dry rock has advantages and disadvantages as well, but that’s a topic for another article.

Aqua-Cultured Live Rock – Pros and Cons

Want to go from empty aquarium to ready-to-go reef in a box as fast as possible? Aqua-cultured live rock is a very fun, quick way to get there.

Some people are die-hard fans of aqua-cultured live rock and others wouldn’t use it if you paid them. As for me, you can now count me as one of the die-hard fans. Here’s why…

This was my new 24g rimless tank two weeks ago:

new 24g tank

This is it one-and-a-half weeks ago:

Tank with base layer of aqua-cultured live rock

And this is it today – fully cycled, already containing several newly added coral frags, and just a couple weeks away from being ready for fish (although I won’t be adding fish for 75 days – I explain why in a future post):

Cycled tank with all 40 lbs of aqua-cultured live rock.

 

The first thing you need to do with a new saltwater aquarium is cycle the live rock you put into it. This usually takes 2-4 weeks when using regular, cured live rock and involves a LOT of water changes and rock scrubbing. And months if you start out with dry rock and cure it from scratch yourself.

By using fresh, uncured, aqua-cultured live rock I was able to cycle my tank in just over two weeks without any water changes and absolutely no rock scrubbing. My ammonia never went above 0.4 ppm.

Using aqua-cultured live rock doesn’t always guarantee a cycle that is this quick and smooth – it is not unheard for ammonia to go above 1 ppm and require one or more water changes. More often than not though it is quicker and requires few water changes than typical cured live rock — and almost never requires scrubbing of the rock.

There are a couple of other advantages to using fresh, uncured, aqua-cultured live rock as well, along with some disadvantages.

The pros of using aqua-cultured live rock:

  • Tons of life on the rocks right from day 1: Since fresh, aqua-cultured live rock has been pulled straight from the ocean floor just few days (or even hours) before going in your tank, it is covered in all kinds, of barnacles, mollusks, sponges, crabs, coral and other life – including ALREADY being home to the beneficial bacteria that live on live rock and make it such a beneficial ‘biological filter’ for your aquarium – which is the primary point of having live rock in the first place
  • It’s eco-friendly: the people who ‘farm’ aqua-cultured rock within the U.S. (and several other nations) are required to use either millennium-old coral rock that has been quarried from dry land, man-made rock, or legally harvested dry coral rock that is then dropped into the ocean populates with the bacteria and other sea life before being collected. In this way, no natural existing reefs are disturbed or illegally harvested
  • It can save you a ton of time and effort:  as you’ve already seen, it almost always takes far less time and effort to go from a new tank to a semi-mature tank versus other types of rock

Of course, like most things in life, it does have trade-offs…

The cons of using aqua-cultured live rock:

  • Tons of life on the rocks right from day 1: Wait, isn’t that supposed to be a ‘pro’? Well, yes… and sometimes no. Most of the life than can come in on freshly aqua-cultured live rock is very desirable – but now and then a few hitchhikers can tag along that aren’t, such as: mantis shrimp, gorilla crabs, stone crabs, whelks, and a few others. It all depends if you’re willing to deal with plucking them out of your tank if any do stowaway on the rock.
  • Slightly less freedom to aqua-scape the rock exactly how you want it: because you are working with randomly sized and shaped chunks of rock that show up on your doorstep HAVE TO go straight into saltwater and are already covered with a ton of life, you don’t have the leisure of choosing, drilling, chiseling, or fitting together a rock feature that exactly matches an aqua-scape you may already have in mind. You’re limited to working with and piecing together the shapes you get.
  • Extra shipping costsreally nice fresh aqua-cultured live rock can be had for between $5-$7 per pound. This compares quite well to the $7-$9 local fish stores frequently charge for regular, cured live rock. However, since the aqua-cultured live rock is so live and fresh it must be shipped overnight in bags of seawater- and this can make for some very significant shipping costs. How much total cost difference there will be between the two will depend on how much your local fish stores charge for their live rock.

If you are interesting giving fresh, aqua-cultured live rock a try there are several places online where you can get it – two of the most popular on the saltwater aquarium forums are Tampa Bay Saltwater (which is where I got mine from – it was a 20g ‘Package‘) and KP Aquatics.

As for me, I’ll definitely be going with aqua-cultured live rock if I set up additional saltwater aquariums in the future.