Tetra Ht10 (50W) Heater Lights Flickering?

[Bettabuddy664]

Hey guys,
 
My heater [Tetra HT10 (50W)] is constantly flickering between the red light and the green light, and at times, the light will turn off at long intervals.
The tank is constantly at around 70* F, which really isn't preferable.
Is it supposed to do this?
 
-BB664
 
EDIT* It's in a 5 gal tank.

 

[jglover]

If your tank is at 70 degrees then your heater is defective. an HT10 is supposed to maintain a constant 78 degree temp. If yours is only getting to 70, the heater is bad....toss it and get another one, preferable one with a thermostat you can set for desired temp. the HT10 is a preset heater.