Is your tank planted? If so, do you use fertilizers?
Is your tank near a window? If not, what light source and how long is it exposed to light?
Does your tank have a filter? Do you have fish in the tank?
You don't want to just start using some product to eliminate the algae. Algae is a symptom. You need to find out what the issue is.
75: blood parrots, featherfin cat, emperor tetras, turquoise rainbowfish, BN plecos, japanese trapdoor; 46: WCMM, gold inca snails, ghost, bamboo & amano shrimp, kuhli loaches, rummynose & ember tetras, endlers, platies, flame gourami, guppies; 16: pygmy, peppered, loxozonus corys, otos, assassins, RCS ... ~ Research PRIOR to purchase.... ~