Ok. So, answer these and we'll get to the bottom of it.
- What type of light
- What color temp
- How long is your photoperiod
- Do you dose ferts
-if you dose ferts what kind
-how often do you dose ferts
-what are your water parameters
-how often do you do water changes
-how much do you change at once
-when is the last time you did a water change
-what do you have stocked in your tank
-what, if any, kinds of plants do you have
-what size tank
-how long has it been set up
-how much do you feed
-what do you feed
-does any direct sunlight hit the tank
-did you have algae problems before adding the new light
-anything else we should know