What is Seachem Flourish Excel?
Seachem Flourish Excel is design to supply carbon for aquatic plants to be use in photosynthesis. However it is not enough to replace the needs of CO2 injection in high-tech aquascaping. That being said, it will be a great help for low-tech aquascape that doesn't have CO2 injection.
How to use Flourish Excel as Algaecide?
Seachem Excel can also be use as an algaecide. Simply turn off the water pumps in your aquarium and apply Flourish Excel directly on top the algae with a syringe. Flourish Excel is heavier then water and it will slowing sink and falls on the algae. Do keep in mind of how much Seachem Flourish Excel is use at one time in this process as excessive dosing will not only harm aquatic plants but also other livestock in your aquarium. Just a small amount of direct dosing is enough to kill the algae. Leave the pump off for around 15 minutes then turn the pumps on again. Repeat the process several days until the algae die off. Some sensitive plants such as riccia can't be use with Seachem Flourish Excel.