It’s not really been the case so far this year, but we associate summer heat with swimming in a lake, delicious ice creams and evenings in the beer garden. But while we enjoy our time outdoors, the temperature inside our four walls at home is rising continuously. Without a fan or air conditioning the persistent heat can become a real challenge, to the extent of precluding sleep and sport.
What effects do these high temperatures have on our aquarium fish? As soon as the room temperature exceeds the temperature you set in the aquarium, the room loses its cooling effect and becomes a factor in heating up the aquarium. Even with good insulation and many precautions, the room temperature can reach the 30 °C mark.
But even if the temperature is "only" 28 °C, the water temperature in the aquarium will rise above the 30 °C mark. The reasons for this are the lighting, the pumps used and a closed aquarium cover.
Tips and tricks for lowering the temperature
Most freshwater fish can withstand temperatures of 30 °C for a few days without any problems. This is because the temperature rises slowly over many days, allowing the animals to get used to it. In a marine aquarium, however, it already poses a problem. That’s why you need to start taking action from 28 °C onwards. A certain buffer upwards is advisable, because the targeted short-term increase in temperature can be used to support disease treatment. If the temperature rises higher, you’ll lose this opportunity. How do you actively lower the temperature in the aquarium and let it rise to a value that is not too high?
The internet is full of short term solutions
- Ice cubes
- Cooling batteries
- Water change with cold water
We strongly advise against this, because these solutions create a rapid change in temperature and only provide short-term effects for a few hours. The rapid change means additional stress for your aquarium inhabitants.
So what can you do without stressing your fish?
- Avoid sunlight: ensure that no direct sunlight falls on the aquarium by closing shutters and curtains.
- Open the aquarium cover: let the heat escape. Evaporation creates a cooling effect. Estimated reduction: 1-2 °C.
- Reduce the lighting time: light generates heat, even the popular LEDs get hot. By reducing the lighting time by 50 %, a reduction of 1 °C can easily be achieved.
- Increase oxygen content: with a bubble stone and an air pump, you can aerate the aquarium and thus ensure increased surface movement and active oxygen input. As the temperature rises, the oxygen saturation level in the water decreases. With these measures you’re therefore preventing an oxygen deficiency caused by high temperatures. Increase the flow: make sure the filter outlet is directed towards the water surface. The strong surface movement provides oxygen input and reduces the temperature through evaporative cooling.
- Switch off some of the technical equipment: all technical devices generate heat during operation. Therefore, switch off all non-essential equipment. This includes, for example, underwater lighting, substrate heaters and unneeded pumps that are not used for filtering or necessary flow generation. Heaters do not need to be removed as they have stopped working by exceeding the target temperature.
Unfortunately, the above measures alone will not be enough to deal with long periods of heat in extreme temperatures. Nevertheless, they are a good basis and worth doing.
If active intervention is still needed, try a flow cooler (aquarium chiller). These devices are very effective and especially popular with cold-water dwellers, but their purchase price and very high power consumption are hard to justify when used only a few days a year. Instead you can place so-called cross-flow fans on the aquarium. The so-called coolers ensure an even and wide-ranging air flow onto the water surface. The evaporation caused by this brings the desired cooling effect of 2-4 °C. Conventional PC fans, which are often tried as a DIY solution, do not bring the air flow over a wide area onto the water surface, do not aim precisely and are certainly not suitable for installation near water. Fish jump and splash and can so come into contact with the installation. We therefore strongly advise against this! The last thing you need is for the fuse to blow, leaving the aquarium without power, or even causing injury to you.
Mount the JBL PROTEMP Cooler x200 (gen 2) and its big brother JBL PROTEMP Cooler x300 (gen 2) on the edge of the aquarium with a stable bracket and align it at an angle to the water surface. An additional controlling device ( JBL PROTEMP CoolControl ) allows you to set a temperature of your choice and the fans will switch off automatically when this temperature is reached.
If the temperature in the aquarium only reaches the 30 °C mark for a few days, this won’t pose a problem for most aquarium inhabitants. Only after many weeks does this stress become a danger for your fish and possibly also cause damage to the plants. We see no reason to "panic" with short-term temperature increases. Nature's example shows us numerous examples of this, such as the Hyperthermal Rockpools. You can read more about this in the blog post linked below.
In very high temperatures it is generally advisable to drastically reduce feeding to a minimum and thus reduce the water load and oxygen demand of the fish. Since plants often also reduce or even stop their activity with high temperatures, you can also reduce fertilisation for this period. Make regular checks of the fertilisation parameters iron ( JBL PROAQUATEST Fe Iron ), nitrate ( JBL PROAQUATEST NO3 Nitrate ) potassium ( JBL PROAQUATEST K Potassium ) and magnesium ( JBL PROAQUATEST Mg Magnesium Fresh water ) so that you can make your adjustments precisely. Check the temperature ( Thermometer ) and measure the oxygen content ( JBL PROAQUATEST O2 Oxygen ) regularly. This way you and your fish will get through the summer unscathed.