The aquarium in summer: heat, vacations ... how to do?

This situation has happened to all aquarists: the temperature rises during the summer. So even though many of us were enjoying this summer heat, our aquariums don't really appreciate this rise in temperature. Indeed, the warmer the ambient air gets, the warmer the water temperature rises as well.

Many fish are now acclimatized to withstand a temporary increase in temperature. But the real problem, beyond the temperature, is the lack of oxygen. Indeed, the warmer the water is, the less oxygen it contains. So how can we make sure that our aquariums don't suffer too much from the heat this summer?

Here are some basic tips:

WHAT TO DO

• Check the temperature of your aquarium every day.

• Check the gas exchanges on the surface: is there enough eddies or is the water stagnant? Improve the air/water exchange and lower the temperature by installing a good surface stirring.

• Lighting generally produces a lot of heat. Reduce lighting time to reduce the heat produced. If this is not enough, reverse the lighting cycle so that it stays off during the day and comes on at night. This way, the heat generated for the lighting system is not added to the daytime ambient temperature, but to the cooler nighttime temperature.

• Leave the cover open to help cool the water. Please note that this only applies to fish that are not likely to jump out of the aquarium!

• If you leave your aquarium open, the evaporation will be higher than usual during this period. Top up the water level with slightly cooler osmosis water, preferably every day.

• Make small water changes on a regular basis with slightly cooler water.

• Do not expose the aquarium to direct sunlight. If necessary, close the shutters. This also applies to outdoor litterbeds, which should not be exposed to full sun during the hottest hours of the summer: place them in the shade in the afternoon.

• Air-condition the room in which the aquarium is located. If this is not possible, keep the room as cool as possible: close the shutters, ventilate only at night...

• Aerate the water surface as much as possible by directing a conventional fan towards the water surface. This is quite effective. Some aquarists use mini-fans (for computer for example) that they fix on the walls of the aquarium. Be careful with your connections with this type of material, not necessarily waterproof. Reserve it for the most do-it-yourselfers! Please note however that you can nowadays find this type of ramp in the aquarium trade, for a safe use!

• Use a cooling unit: it is THE ideal solution. Too bad it's not within the reach of everyone...

• The technical equipment needed for the aquarium produces heat. For example, the motor of the filter pump converts part of the electricity into heat. If possible, opt for external filtration.

• The installation of an air pump (bubbler) helps to re-oxygenate the water efficiently (caution, may slightly vary the pH).

DO NOT DO

• Do not unplug the heater. Immersion heaters are equipped with a thermostat and therefore do not operate above the desired temperature. For example, if your heating system is set to 24°C (75°F), and the water is at 26°C, it will not operate. It is therefore useless and inefficient to turn it off.

• Do not make large water changes with cooler water. Fish do not appreciate large temperature changes that cause thermal shocks that can be fatal.

• Same problem as above with the use of frozen plastic bottles placed in the aquarium to cool it down. We do not recommend this technique as it will cause the temperature of the aquarium to fluctuate uncontrollably. The water will drop in temperature sharply when the ice is introduced, and then rise quickly once the ice melts. These variations, contrary to relieving your fish, will put their health to the test by subjecting them to important thermal shocks.