New to the forum and new to being a pool owner. We moved into a house with an In-ground marcite pool of around 15,000 gallons. There are two main drains at the bottom of the deep end that are not sucking. I'm assuming they are plumbed together. Just off the pool concrete is some PVC pipe that comes up and isn't hooked up to anything. I pushed water through this tube and it came out of the main drains at the bottom so now I'm left to believe that the drains aren't hooked up. Right next to this 2" PVC pipe is a capped off 1.5" PVC pipe that I'm assuming goes to the pump. You can see this pipe in the picture attached at the bottom left of the picture. Before I go hooking this back up, I have a few questions. Why would one side be 2" and the other 1.5"? Is there typically a filter basket here above ground because the main drains suck more? I have not removed the cap from the 1.5" side yet. I don't want to do that till I'm ready to reconnect. Any help would be great!!