Hi, I have a Polaris 360 and I have 2 pool returns (where the water comes out of). My pool is very old and the pool return is just made of plaster. One of them is big enough so I just stuck in the polaris hose pretty deep and it stays there alright. However I don't get enough pressure because there is a second hole. I tried to plug the second hole with a cork (it's smaller), but it keeps falling out due to high pressure. I have managed to temporarily block the second hole (maybe for one day before the cork slips out), and the polaris zips along just fine.
What can I use to block the second hole?
Edit: Does anyone know how I can make the pool blue color? The plaster is white but I went to a party this weekend and they had a blue color pool and it makes it look so clean. My water is fine but white doesn't look as clean for some reason lol.