Heating is important in any aquarium, its essential to replicate the temperature found in the ocean, as temperatures often change, especially in winter. Thermostat- heaters are the answer to the heating needs of your tank, a thermostat-heater can be adjusted to a temperature you want your aquarium to maintain by adjusting the knob found at the top of the unit, it’s always good to keep an eye on the heater and check the tanks temperature. Heaters have been known in some cases to malfunction causing tanks to overheat and crash killing everything in the tank, so it’s important to keep check of the temperature in your tank at all times, this can be done with a digital thermometer. You can get fully submersible ones that go inside the tank or you can get digital external thermometers which stay on the outside but have a probe that goes inside the tank. The recommended stable temperature you want to keep at all times is between 27°C (80°F) and 29°C (84°F), stability is important.
Cooling the aquarium has not been that big of an issue in the UK, until recently. We have had short but hot summers and for aquariums this can spell disaster. I had to turn my heater off and buy a fan cooler this helped but I was constantly having to top up my tank with water as the combination of the fan and the heat made the water evaporate quite fast, I bought the fan as a quick fix solution. A real solution to the problem is buying a chiller, fan coolers chillers are very effective at controlling the temperature in your marine aquarium, water passes through the chiller and is cooled to the desired temperature then the water is returned to the tank keeping the aquarium at a stable temperature, the only downside is they are ridiculously expensive, if you are in a hot country then you most probably will need one, but in the UK we only have a month or two of hot weather and then it’s back to winter for the rest of the year, so I could never justify spending £300 or more on one, so I opt for the £35+ cooler fans option and keep topping up. But if you live in a hot country, or have an expensive reef setup then it’s worth investing in a chiller, it’s really not worth the risk of losing all you have spent, built and worked hard for.