Saving electricity, now there’s something that everyone is interested in. Usually usage can be lowered to a greater or smaller extent.
With the marine aquarium it starts at the planning stage. Buying the correct size heater(s) is important, buying smaller ones doesn’t help, they’ll either be inadequate to the detriment of the livestock or switch on and off regularly achieving nothing. There is always the potential for an oversized heater to go wrong. It could stick in the ‘on’ position and overheat the seawater quite quickly. A correctly sized heater could stick of course, but the seawater will heat up more slowly increasing the chance of the aquarist spotting the temperature increase. A good idea, although it does increase the setting up cost, is to use an external heater controller, one that has a sensor in the seawater. The actual heater is set two degrees higher than the controlling thermostat unit meaning the heater is always in the ‘on’ position. Thus the thermostat is in full control of the heater. Don’t expect the thermostat unit to be accurate in its settings indicators, always check the seawater thermometer. Accurate temperature is important in saving electricity, too high or low a temperature is a waste or a danger to livestock.
The temperature of seawater should be between 68F (20C) and 86F (30C). Running the temperature at the two limits or close to them is not acceptable because of livestock health and behaviour changes. It is best, for the livestock and economy, to run at a temperature between 75 and 80degF (24 to 27C). Many run at 77F (25C) as an acceptable level. The livestock come first and as this temperature is acceptable to them and not excessive in electrical demand then there’s the answer. Some advanced aquarists up the temperature for specific reasons but most aquarists stick to the normal temperature. It is safe for the livestock and minimises the demand for electricity. To achieve the required temperature use a heater rated at 2 watts for each gallon if the room is heated, if there isn’t any room heating 4 watts for each gallon. If there are doubts then use 4 watts. Remember that the gross gallonage of the aquarium will be reduced when rocks and sand are introduced. The gross gallonage of the aquarium is easily known. To discover the net gallonage either have the rocks and sand in place when the aquarium is filled and measure the seawater as it goes in (not a useable system if ‘live’ items are being introduced), or measure the amount removed when the rocks, sand etc are introduced (not so easy with sand). This sounds a messy way of doing things but it works. A better way is to put the sand into the aquarium and measure from the top of the sand in order to calculate the gross gallonage, then when the rocks go in measure the displacement. The sand allows seawater to penetrate of course so it isn’t fully accurate but it does work. At the very least, use an acceptable percentage reduction as suggested on the net at a reliable source. Heaters, best when controlled by an exterior thermostat, contribute largely to the electrical demand of the aquarium. As said, large and small heaters could be similar in demand, smaller ones staying on longer, but it is safer to use correctly sized ones.
Ok, what else could be done? When setting up the aquarium, consider conserving heat and thus saving electricity. If this is done, there should be less demand on the heaters. At the setting up stage sit the aquarium on a sheet of polystyrene of good thickness. This will cushion the aquarium base and provide insulation. With a new set up or already set up aquarium, use polystyrene on the back and sides. Polystyrene is normally white and this doesn’t look good when viewing the aquarium so before it is put in place paint it, it’s easily done. When put in position it enhances the appearance of the reef or other decorations. The sheets can be cut very easily and put into place with silicone glue. Thus the aquarium has stopped being a radiator, at least on the sides where the insulation has been applied. This should save a good few watts.
There are some aquarists in warmer areas who do not need heaters just a cooler. These use electricity as well of course and the same principles apply, making sure the temperature is set to an acceptable level for the livestock and with consideration for saving electricity. The use of insulation also applies, though this time consideration has to be given to whether heat loss is good which it could be, heat loss could mean the cooler has to be active less often. In very warm temperatures, it could be in reverse, the insulation could help stop or slow down heat absorption from the air.
A separate heater is required for the partial seawater change. The same principle can be applied. The amount of seawater for the partial seawater change will be known and this amount is normally the same on each occasion. So again the heater can be the correct size, kept purely for the exchange seawater preparation.
There’s other items that consume electricity but these can’t be interfered with, such as lighting, circulators, skimmers etc. However, as long as the demands of the livestock are considered and the heaters are correctly sized and set up the ongoing running cost of the aquarium is reasonably controlled.
The aquarist should always keep an eye out for advancing technology. This in itself could save running costs. Though new technology can be expensive it often saves electricity. For example, once many reef systems relied on metal halide lighting, now LED systems are available. LED systems electrically are very reasonable to run and also often offer the aquarist extras such as automatic dimming and the like.