Argh! – A Power Cut – What Do You Do

A power cut can happen at any time however with the colder months now coming power cuts do appear to be more frequent – dependant upon where you live of course as you may be lucky and not get any.

A power cut falls under two areas of interest to the aquarist – one that is known about and one that is not.

If a power cut is known about then it can be planned for. For example if you find out two weeks prior then you can obtain an alternative source of power – a generator for example. The decision to obtain a temporary power supply does depend upon how long the power will be out for. If power goes out for only a short while then there are things which can be performed however these will be covered a little later.

The second and in my opinion the more worrying one is where the power cut is not known about. It can happen at any time, day or night and you will have no idea how long the power will be out for. Again in this instance you can rush out and get a generator but what if it is the middle of the night, what if you cannot get one etc. There are things you can do to protect your aquarium which I will cover soon but for now let’s pretend that you do not have any protection and a power cut has happened.

If a power cut happens then all the equipment strangely enough will stop working. The aquarium will be plunged into darkness, there will be no water movement, the heating will be off etc.

The area which you need to worry about primarily is the heat. The aquarium is going to cool down and it will do so quite rapidy. Your main concern right now is keeping the heat in the aquarium. You will can not stop it cooling down but you can slow down the cooling. One of the things you can do is wrap bedding or something else which is good at retaining heat all round the aquarium – bubble wrap is another good example. You will need to keep a very close eye on the temperature and if the temperature drops then realisitcally you need to locate an alternative source of power.

Another area which you need to monitor is water movement. The powerheads, pumps etc will all have turned off when the power went out so there will be no movement whatsover in the water. This does not matter for the fish and for a short while even the corals however the air content in the water will rapidly be depleted. Therefore once you have done something to try and keep the heat in then you need to provide some type of water movement. This is quite easy to do and can be done with a wooden spoon or even your hand. Basically all you are looking to do is break the water surface and move some water around. This will allow of air exchange to occur and a small amount of movement will occur in the aquarium.

Another thing to consider is the filtration. If an external canister is being used then this will have turned off so the aquarium is not being filtered. If live rock is in use then the filtration is still active however with no water movement it is not effective. At this point it is not a concern however you will need to keep a close eye on your fish, corals etc.

You should not worry about lighting. The fish etc will simply believe it is night-time and will retreat into the rockwork. They may not appreciate being plunged suddenly into darkness but it’s tough really as there is not a great deal that can be done about that.

The hard thing about an unexpected power cut is that you will never know when the power is going to come back on until it does. What I would recommend is that you monitor the aquarium closely and if the fish show signs of distress, the temperature drops etc then you need to go and locate another source of power. If it is late in the afternoon and the shop which hire them shuts soon then I would go and get one anyway. If it gets late at night and the power is still not on then you will not be able to get one and your fish etc may not make it through the night.

It does need to be noted that the above will only work if you get to the aquarium in time. If it is the middle of the night when the power goes off and you are asleep then you are not going to notice the power cut until when you wake up. By this time the aquarium may have cooled to such an extent that attempting to keep the existing heat in will not work. At this point you need to get some heat into the aquarium and to do that you need power.

There are ways to protect your aquarium livestock from a power outage. The best one in my opinion is using what is called a UPS (Uninterruptable Power Supply). A UPS is basically a lot of batteries which sits there waiting for the power to go out so they can jump into life. When the power is on the power passes through the batteries and keeps them charged up. When the power goes out the batteries provide the power.

A UPS can be purchased in numerous sizes – the larger ones obviously providing more power that the smaller versions. It does need to be noted that you should not plug all of your aquarium equipment into the UPS. If you do and the power goes out then the aquarium will continue to function however the batteries will not last as long. Basically all you need to keep plugged into the UPS are the items which are essential to keep the aquarium running during the power outage and for the longest possible time possible.

In the UPS all you need to plug in is a heater to prevent the temperature from dropping and a powerhead/pump to provide water movement. If external filtration is used, for example a canister filter then this can be plugged in. If a sump is used then I would also plug in the return pump and discard the powerhead as the return pump will provide enough water movement for the time being. All other items although required during normal operational running can be plugged into the standard power outlets and accepted that they will not be working if the power goes out.

From the items you plug into the UPS you will then be able to work out how long the batteries in the UPS will last for before they become flat. Remember the more you plug in the faster the batteries will drain. A UPS when used on an aquarium is there to protect the livestock for a short amount of time. Power outages of just a couple of minutes will be ok just running on UPS however for power outages of more the UPS simply gives you time to locate an alternative source of power.

  1. I used a jump starter battery and a £25 inverter from amazon to run the air pumps (4W), and an old UPS (2.5kw) to run the filter (6W).

    To mitigate the heat loss I tossed a fleece blanket and a winter tog duvet over the aquarium (125l).

    That kept me good for 8.5 hours while they re-rigged the powerlines outside my house.

    A couple of car batteries and two 300W power inverters should keep your essentials running for around 9 hours.

    Something I found frustrating is the car battery wouldn’t run the Fluval U3 filter. The motor seems sensitive to imperfect sin waves, while my Eheim air pump ate it up.

  2. Hello Calvin. You’re certainly organised, very good! Hopefully any power loss will be of short duration and the main concern is heat loss. Power supplies are pretty reliable nowadays but, as with many things, it’s best to be prepared or at least have the knowledge on what can be done should the unexpected appear.

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