When inserting the foam rope in the main drain and the return jets, is it supposed to go straight in, or is there some bending and cramming involved? I am a first time pool closer and my pool is 3 years old. When I try to get the foam rope into the main drain, it can't go down because there is water there and it just floats up. I'm not sure if I am supposed to suck all that water out of the main drain with a shop vac. Can you please advise?