Hello!
OK, first off, do NOT use chemicals. They will cure NOTHING.
First off more info is needed:
Tank size?
Filter type?
Age of tank - how mature is it? Is it cycled?
What substate do you have?
How many fish & what types?
What kind / qty of lighting. What lighting period do you use?
What ferts (of any) do you dose / qty / how often?
Recent tank activity? Up rooting / new plants / new lighting / new anything / changed anything / added new fish / added anything etc?
Reading for Ammonia, Nitrite, Nitrate, GH, pH, temperature.
How long has algae been present? Did you alter ANYTHING and then see algae? If so, what did you do?
Answer that lot and solution will come soon (I hope)...
Andy