Can you post some pics of your pool? I suspect some of your issues are the size of your pool. It is very large for a residential pool. I know someone else that has a huge pool and it is not large because it was well thought out and the builder did a good plan, it is large simply because it was an owner build and the owner owned a concrete company. It has a VERY poorly laid out plumbing plan. No thoughts to anything but making it "large". He is also having algae issues like you. Water circulation has to be well thought out on a large pool. If you only have returns on the sides of the pool, that could be an issue. When you get into that large a pool, little things become big things. At a minimum, you should have floor and wall returns. I'd do a test if I was you with some food coloring in the water and your pool running full speed to see where the dead spots are. One way to mitigate that is to have the vacuum running all the time to help circulate the water.