So I have a 75 gallon aquarium and have been running 1 rw-8 for the past year. I have noticed quite a few dead spots and areas not getting enough flow even though I have it at 100% and cleaned it monthly. So I decided to order another one which is a pp-8, got it today and set it up. I have been going through the settings with them synced and cant find one I like. I have them both at about 30% and they are blowing sand all over I dont get it. I'm looking to the the simple swaying back and forth motion of the corals. What settings and position of the 2 heads do you guys suggest? Thanks!