One week ago I had new 18' AG pool installed & water delivered. I had chlorine tablets in a floater but I just hooked up & turned on my pump & [DE] filter yesterday. Water is crystal clear, I'm in the process of balancing out the chemicals. My problem is this... at the bottom center of the pool is what I assume to be algae of some sort?? (please see picture) With my former pool we definitely had an algae problem which seemed to be concentrated in the same exact spot. With my former pool no matter what chemical/vacuuming combo we used it would go away only temporarily, always came back. I am by no means a pro when it comes to pool chemistry but I know I do NOT want to start off with the same problem with this new pool. Please help! What is the best way to get rid of algae (if that's what this is) once and for all? Why the center of the pool? The filter has been cleaned and water seems to be circulating fine. I'm perplexed. Has anyone ever heard of or used a product called Kleen Pool? Recommended or no?