We all know how dangerous the high temperatures are in saltwater reef tanks. Some aquarists even report catastrophes in their own tanks as hundreds of dollars' worth of livestock are heated and killed. So, it's amazing that there are so many different ways to lower the temperature in your aquarium.
First, let's talk about why high temperatures are so dangerous in marine fish tanks, especially in reef tanks. All organisms wish to maintain homeostasis, a state of internal equilibrium.
Of course, you want to regulate the temperature of the aquarium and it is best to keep the temperature stable. Undoubtedly, the best way to keep things stable is to buy an aquarium chiller as it will keep your tank temperature where you want it to be at a fraction of a degree. You can also buy jbj arctica water chiller via https://www.marinedepot.com/jbj-arctica-titanium-chiller-1-10hp-dba-07
They act as a built-in filter with a cooling coil much like a refrigerator. The ability of a chiller to cool a tank is measured in horsepower and the size of your tank will determine the power of coolant you need.
Another advantage of chillers is that they have a built-in heating element so there is no need for additional heating in the tank. While the coolers are accurate, they can be very expensive, especially if you have a larger aquarium. The 1/10 hp JBJ Arctica Chiller costs nearly $500-$700 but cools on a 65-gallon tank.
If this option doesn't work for you, you can always use an easier method, such as a fan blowing through the surface of the water. This idea works like a sump cooler, causing the water to evaporate and carry extra heat.
If you're desperate for heat control in a pinch, you can drop the ice pack to help bring down the rising temperature quickly. However, this is not the best long-term solution because you have to do it all the time you make a difference. In addition, you will need to constantly monitor the temperature in the tank to know when to add ice.