We currently have a sunken tub and I'm going to replace and raise the tub. I have everything figured out except the drain. The drain is going to have to be moved up since the from the tub drain to the P trap is going to be raised up 22 inches? I was told that that long of a drop will cause the P Trap to siphon. In order for me to put the P Trap as close to the tub as possible, I then have to connect the P Trap outlet to the main drain directly below to where the old P Trap is. The question is, how do I do this? If I come straight out of the P Trap, I have to 90 down and then 90 back into the main drain. I can't really move the main drain because it only has a 12 inch opening from where it comes through the slab. With two 90's after the P Trap, will the water still move freely? All piping is 1 1/2 wide. Thank you!