heater issue

Hello,
I have a 75 gallon Reef tank that has been up and running for 2 weeks. I have a 250 watt ("heats up to 75 gallons")Marineland Stealth heater. However, even set as high as 83 it only keeps the tanks at 76 at night. During the day my lights are increasing the temp to 79. So it appears I need to buy a new heater or a second heater. The current heater is producing heat but not enough. Should I purchase a second 250 watt Stealth heater or just purchase a different brand? (My main concern is currently having to much temp fluctuation for my Coral Beauty and Yellow Polyp).
Any suggestions would be appreciated,
Thanks,
Jim

75 gallon Reef tank 29.5 lbs of live rock,54.5 pounds of base rock, 40 lbs live sand, 6 Green Chromis, 1 Coral Beauty, 1 Peppermint Shrimp, 5 drawf hermit crabs, and 9 snails

 

You don't have it plugged into the timer that your lights are on, do you? If so, that would shut off your heater at night. You may want to get a 300 watt, or maybe just return it if your particular heater is faulty.

 

I use a Marineland Visi Therm 300 W heater for my 80 gal. Temp is set on it for 78 and stays at that unless its a really cold nigh then it only drops to 76. Heaters - MarineLand Visi-Therm Deluxe Aquarium Heaters 300W

 

I am using two heaters, a 250 watt. marineland heater and a 200 w. stealth heater. I noticed that because it's winter, and the tank is in my basement, my temp was getting down to about 74-74 at night since I added a sump, so now I have the two heaters and my temp. stays at 77 all day and night.

 

You probaly should have two heaters regardless. Reason being incase one fails it will take up the slack for the broken one. It allows you to notice it without loosing livestock. Just a redundant system. I have two 100 watt heaters, and they keep my 72 gallon at a perfect 78 all the time.

 

I got a 300w titanium heater of the bay for around £19 they're great, i only have a 42 gal and i used to have to have 2 * 200watt glass heaters to keep the temp steady.

Thanks


Matt