Algae adjectives are listed in this post. Each word below can often be found in front of the noun algae in the same sentence. This reference page can help answer the question what are some adjectives commonly used for describing ALGAE.
bluegreen, brown, calcareous
celled, certain, filamentous
freshwater, green, marine
microscopic, other, photosynthetic
red, symbiotic, toxic
Hope this word list had the adjective used with algae you were looking for. Additional describing words / adjectives that describe / adjectives of various nouns can be found in the other pages on this website.