After water quality and then lighting water circulation, in my opinion comes next.
Not just any water circulation though – you can’t just chuck powerheads left right and centre into the aquarium and turn it into a washing machine – you have to create the right water flow.
The water flow which you need to create depends upon the livestock you keep in the aquarium. If you are a fish only aquarist then the water circulation requirements are minimal. Corals, however are more demanding in water circulation for various reasons.
Years ago the only option which was available to saltwater aquarists was the powerhead and to be honest we had to be creative as to the ways we positioned these powerheads to achieve optimum results.
Nowadays as both manufacturers and aquarists have learnt more about the requirements of the animals we keep there are more options available to us.
There is one option which I believe stands out above the crowd though and that is one which is called closed loop.
Closed loop circulation is where the device which creates the waterflow is housed external to the aquarium, quite often beneath the aquarium, however it can be placed anywhere. Rigid or flexible tubing is connected to the device which connected to both the inlet and outlet of the device which both go to the aquarium.
A lot of aquarists who use closed loop circulation opt to drill the aquarium and use bulkhead connectors and taps to connect the external device to the aquarium, however you do not need to do this if you don’t want to – you can go up and over the edge of the aquarium if that is easier for you.
Basically what you are doing is allowing water to be pulled from the aquarium to the external device, we will use a external water pump for this example. This pump then pushes the water along the output back into the aquarium and whilst doing this pulls more water behind it.
Now here is the good thing. In a closed loop circulation system there is no air in the pipes which means that there is no head height plus as the pump is external to the aquarium there is no heat transfer from the pump to the aquarium water.
You can setup as many closed loop as you want however each one will require it’s own dedicated pump. A huge benefit of this is that with clever plumbing you can take water from the aquarium from exactly where you want it to be taken plus you can return it to an area in the tank where you want it to be returned to.
One thing I must point out though is that if you do decide to opt for a closed loop system then I would recommend that you install close off taps to both the inlet and outlet areas of the plumbing. Doing this will allow you to remove the pump it either it requires maintenance or replacement.