Hi Bob,
I read your column in FAMA and I have a question concerning heaters. I previously maintained a 10 gallon micro reef for about 3 years and I'm now upgrading to a 75 gallon reef with a sump and skimmer. My question pertains to heater wattage. I have numerous books and have seen recommendations as low as 2 watts per gallon and as high as 8 watts per gallon. I'd like to install 2 heaters in the sump, each running off a different surge protector. The sump will probably hold 10 - 20 gallons when running. None of the recommendations indicate if that is for total water capacity or actual water volume which will differ greatly once the rock and sand is in. I know both too high or too low wattage will both be ineffective. I'm thinking about using two 150 watt heaters. Do you have any thoughts or recommendations on this?
Thanks,
Jeff
Hi Jeff,
For heater sizes my rule-of-thumb is 2 to 4 watts "per total gallons in the system." Keep in mind should a heater malfunction it will take longer to overheat an aquarium with a lower wattage heater than one of higher wattage. Even in colder areas where a higher wattage heater would prevent large swings in temperature I would recommend using two or more smaller wattage heaters than a single high wattage heater so as to prevent a possible fried fish situation.
Placement should be in an area where there is sufficient water movement. Insufficient water movement past the heater can cause a high heat area near the heater possibly stressing any animal that comes too close. Sump areas where there are no snails and other slow moving animals are an excellent place. When installing a new heater allow for the unit's internal temperature to match the temperature of the aquarium water before plugging it in and setting the temperature. This may take about an hour. Stay with name-brands.
Hope this helps,
Bob