Live rock as has been said time and time again is a phenomenal filtration medium. There are various different types of live rock available all of which provide the required filtration to the aquarium if enough is placed into the aquarium.
There is one in particular however that in my opinion is more decorative and ‘standard’ live rock.
Tonga rock is different to other types of live rock due to the reason that it looks like branches of a tree. It can be an extremely decorative addition to a saltwater aquarium. Due to tonga rock being thinner and not boulder shaped like the majority of other live rock with the obvious exception of plating rock you have the ability to be able to create fantastic water movement around it.
In my opinion tonga rock is fantastic for SPS corals as you can provide a large amount of water movement and if carefully aquascaped can look amazing. This is not to say that you could not have a fish only aquarium or a soft coral aquarium with tonga rock as you would be able to. You would just have to bear in mind that you will need to create caves etc for the fish to hide in as well as creating ledges to place the soft corals on.
But what about the filtration – is tonga rock as good as other live rock.
Tonga rock does have good filtration capabilities however they are not as good as other live rock. This is mainly due to the size of the physical rock. To purchase enough tonga rock to faciliate the filtration requirement would make it very hard to aquascape.
So what do you do?
In my opinion it is quite simple. I personally would use the tonga rock for decorative purposes and then have an in tank deep sand bed as well. The deep sand bed would be the main aspect of the filtration but the tonga rock would do some as well albeit reduced. You do not need to have the deep sand bed in the display aquarium it could be in the sump in the cabinet. You would just need to make sure that the partiton designed for the deep sand bed was large enough.
One of my dream aquariums (we all have them don’t we) is to have a 3 foot cube tank (3*3*3). In this aquarium a deep sand bed would be placed and tonga rock used for decorative purposes as well as some plating rock to provide some hiding places/ledges. Lighting would be provided by metal halides, the water movement would be chaotic and my corals of choice would be SPS with a small amount of fish.
We can but dream can’t we?