How to Cool Down the Water in Fish Tanks. You should always keep a thermometer on fish tanks to help control the temperature. Usually a heater is installed to warm water, but there are times when the water needs to cool down. This is a good deal harder than warming the water.
Things You'll Need
- Air conditioning
- Water bottles
- Electric thermometers
Turn off the lights. This is one of the main sources of heat in an aquarium. If you can, simply turn off the lights completely and then monitor the temperature to see whether it drops. As water cools down, you can figure out how long lights should be left off each day.
Change your lid. Glass tops create a humid greenhouse effect in your fish tanks. Try removing the lid completely, or purchasing one that allows more air circulation. This will cool down your tank drastically.
Move the fish tank away from direct light and windows. This atmospheric heating causes water inside tanks to heat as well. This is especially important if you live in an area where temperatures rise above 100 degrees in the summer.
Cool the room that the aquarium sits in. Outside temperature affects water in fish tanks, so try cooling the room. If you don't have air conditioning, try fans.
Replace water with cooler water to lower the temperature quickly. Only change about 10 percent of the water and be sure to monitor the temperature, so you don't shock your fish.
Freeze a bottle of water and let it float in the tank. This cools the water without mixing in new water. Larger tanks may need more than one bottle. Just keep your eye on the temperature, because it should drop slowly. Remove the ice if the temperature plummets.
Install fans near the lights to cool the temperature of the lights. You will need to raise the lights about a foot (depending on the size of the tank) and the cross fans beneath them. You should apply a cover below the fans to avoid disturbing the water.
Attach a thermostat or controller to the lights, fans and heaters, so that the right elements turn on as temperature fluctuates. This removes some of the pressure on you, but also lets your fish live in optimal water temperatures.
Keep the water circulating. You may want to add another filter to aerate the water more or a simple air pump. Adding the extra oxygen also helps the fish breath, as warmer water has less oxygen than cooler water.
Buy a thermoelectric chiller. Some double as a heater. The coolers need to be installed partially in tanks, so drilling may be required. These are expensive and may not be a wise investment for a small tank.