Summer is almost upon us and with it is the problem of our reef tanks becoming too warm. This statement raises several questions: what is too warm, what are the consequences of too warm, and what to do about it. Although I can only give anecdotal answers to these questions, my observations are based upon many years of experience, both with my own reef tanks and those of other advanced reef keepers.

Too warm

A sustained temperature over 84-degrees F is too warm. Furthermore, my experience suggests that a sustained temperature over 82-degrees F is too warm. It is almost always during the summer months that we hear about reef keepers having problems with RTN (rapid tissue necrosis). Exactly why this is so is still a matter of speculation. It may be that the higher temperatures strain the coral animals metabolic processes; it may be that predatory bacteria gain an advantage at higher temperatures; it may be that the capacity of water to hold oxygen is reduced at higher temperatures; it may be that the higher temperature raises the metabolic processes in all of the animals in the reef tank and thereby altering in a negative way the balance between the producers and consumers of waste, and it could be a combination of all of the above. And, it may be any number of other biochemical factors that I haven’t thought of. Bottom line, sustained warmer temperature brings with it problems for reef
keepers.

Solutions

The obvious solution is a chiller, but the cost of a chiller along with the cost of its energy consumption will strain many pocket books, especially those with large reef tanks.

One solution, by the late and much missed reef keeper Greg Schiemer was an air conditioner in the room that housed his 500-gallon reef tank. And, he connected all of his metal halide fixtures together and vented their hot air out of the house via an exhaust fan and dryer type duct.

Another solution is to direct air from fans across the surface of the tank’s or sump’s water.

Still another solution is to only turn the bright reef lights on at night when the house’s ambient temperature is generally at its lowest.

In small tanks it is possible to use ice cubes to lower the temperature, but be sure to put the ice in sealed bags so that their melted water doesn’t enter the water column of the tank.

It is even possible to run coils of a cold water hose in and out of the tank or sump, but this only makes sense where the cost of water is very inexpensive.

If some reef keepers have other solutions please inform us here.

My freshwater tank is thriving, and the 3 to 4 inch discus fish are doing very well competing for food with the rest of the fish, but the large red dragon is still not eating well and appears very shy, too shy to compete successfully for food. Any discus lovers out there with advice about this will be appreciated.

Finally, my Kribensis continue to spawn, and are quite successful at guarding their young. See photo below!

Kribensis cichlids in the author’s tank.