The frequency of how often a filter cartridge should be changed will vary according to how much waste and free-floating algae is in the fish tank. The general recommendation is to change the filter cartridge once per month.
The duration of light needed in will vary. Aquariums with artificial décor need 8 to 10 hours of light per day, however, aquariums containing live plants will need about 12 to 15 hours of high quality light per day. Hours of light should be the same each day as fish rely on a daily rhythm for their activity and proper health. Use a timer to provide a consistent day/night cycle. Avoid placing an aquarium in sunny location or leaving the light on all the time as it can cause extreme algae growth. Watch our short video on the 3 Tips to Succeed to learn about the key tips we recommend in fishkeeping.
No, simply seeing condensation inside your Aqueon Glass Adjustable Heater does not that it is broken or defective.
Check that the heater is working properly by using a thermometer with your fish tank. (also make sure that the water is the right temperature for the type of fish that you have inside your fish tank)
The reason you may see condensation is because humidity was in the air and trapped inside the tube when it was manufactured and sealed. Your heater is still able to perform properly with this condensation.