First year pool owner. I have a vinyl IG pool, about 15000 gallons, maybe a little less. Hayward 36sq ft DE filter. I am having an issue with dirt etc. coming back into the pool through one of the returns. My pool guys came out and said the filter looks fine and it is probably a crack in the pipe somewhere and the dirt is getting in and they will cap off that return. They said something about a pressure test also but then left. (Only my wife was home when they came so I this is all the info I have). I have 2 returns over the steps (one of these is where the dirt is coming out) and 2 more returns around the pool. I assume the pipe can be replaced but that seems like it would be a lot more difficult. Is it fine to just cap it off?