I did put some Algae killer that I purchased from the pets store. Though it did say 1 tsp for 10galls and I put about 1 - 1.25 litre's into my system to fill it up. Now my question is , by putting more then I probably should , would that result it it basically not doing it's job? My res is clear as the day when I first put water in it. Though in my tubing , I can see a little layer of something.