When a heater/stat is purchased check the size (wattage) is sufficient for the gallonage to be heated, and also check the variance of the stat – this is usually stated on the packaging or, if not, on the instructions. Heater/stats are available with a variance of +/- 1 deg F. Seawater cools slowly (cooling speed dependant on the gallonage and surronding air temperature) and around 2 deg F or even 3 should not cause problems hopefully.

If closer control of the heater/stat is required without buying new heater/stats then an external controller can be used. These are electronic and usually come in a small plastic box. One ‘end’ goes to the electricity supply and the heater(s) are plugged into the other. A probe sits in the seawater. The required temperature can be set often by means of a dial. The heater/stats are set around 2 deg F above the setting on the external controller.

Have suspected we in general keep our average aquraium temps too high…even while recommended by many.

Now hot weather upon us, I feel much better keeping lower ave temps in tank after reading your article…going to shoot for 77 degrees in my primarily soft coral tank also.

Thanks,

Scott Davis
Silverdale, WA