Pool growth is the increase in size of a pool over time. The two crossword solutions for the term pool growth are ALGAE (5 letters) and ALGA (4 letters). ALGAE are a group of aquatic organisms that range from single-celled microorganisms to large seaweeds. ALGAE are found in both freshwater and saltwater environments, and they are an important part of the food chain. ALGA is a singular form of ALGAE, referring to a single organism. ALGAE are important for pool growth because they provide oxygen and nutrients to the water, which helps to support the growth of other organisms.