Dead Spots....

I have a 150gal fish/invert/liverock tank and have a few dead spots in my water. Do I need to add power heads to stir the water in the dead areas in my tank? Would this help reduce my phosphate and and amonia levels? I have a pretty good wet/dry system with an in sump berlin turbo skimmer. My main pump (sequence dart 1/4hp 1550rpm) pulls the water from the wet/dry and sends it into a T splitter. From there the water travels two different paths... one side goes through my coralife 6x UV and then into my chiller which returns the water to the top center of the tank....the other path from the T splitter sends the water through an alternating wave maker that I have placed at the top back corners of the tank. The dead spots in the water are below these wave maker outlets in the bottom rear corners of the tank.
My fish are large waste makers and sometimes I can see a build up of waste in these dead spots. I have an adult emperor angel(heavy waste maker), a med size clown trigger, a small kole tang, two true perculas clowns, a longnosed hawk, 4 blue damsels, 3 black hawaiian brittle stars, 2 coral banded shrimp, several assorted hermit crabs, and about 50 pounds of liverock.
I'm sorry for the long post, but I would really like to get rid of my high phosphate levels and start growing some more coraline on the rocks that aren't live.... any help is appreciated.

rp

right now i do not have any power heads in my tank. I rely solely on the main pump to stir the water with the return from the chiller and the wave maker that alternates from one side to another. I will add a couple of powerheads tomorrow and see what kind of difference that makes.

I am using natural seawater for my water changes. The Waikiki aquarium pumps water from an underground sea aquafer, airates it, and gives it to their members for a small yearly donation. For my freshwater top-offs I use filtered tap water. I will test my filter water and see if that may be a contributing factor in the phosephate build-up.

Thank you for the help...

rp

I did a partial water change today (about 40gal) and removed the visible waste in the dead corners in my tank by vacuming the sand. I also added two power heads (maxi-jet 1200) at the lower back corners of my tank and am using the maxi-jet wavemaker power strip to cycle power between the two. I am also using the Swiching Curent Water Director (scwd) powered by my main pump.
I think the addition of the two new powerheads will greatly improve my water quality. They create quite a stir through the tank. I don't think I will have the problem of waste build-up in the corners anymore.
I am going to my lfs tomorrow to pick up some phosban and add that to hopefully get rid of some of the phosphate in the water. I am hoping to see a reduction in ugly brown alge and a rise in good coraline growth.

after reading your posts i tested the seawater i get from the aquarium and it is loaded with phosphates! So right now i have "coralife phosphate remover" in my wet/dry and am cycling about 50gal through a makeshift phos filter in a barrel to prepare for my next water change.
I was told that the water i get from the aquarium was "perfect" so i didn't bother doing any tests on it.... lesson learned. thank you all for your help.

rp