Couple of complications
Couple of complications.
1. As the previous person mentioned, most people find that the light contributes too much heat to their system. I know mine does, which is why I have a chiller.
2. If you're always pumping water through the light system, you don't have much control over the temperature. Adding a temperature controller (like I use for my chiller) is expensive.
3. You'll still need a heater for when the lights are out and when the tank is most likely to need it (i.e., at night when the temp drops and there are no lights warming the tank).