I am in the process of completing basement reno. I got a plumber in to do the rough-in plumbing and I am completing the installation of the fixtures. The plumber has run plastic tubing to all the floor drain traps to ensure that there is always water in the trap. This tubing has beeen routed to where I will connect the laundry tub and washing machine. My question is: how to I connect the plastic tubing into the drain line so that water from the washing machine will keep the traps full of water?