Wave makers blowing sand. Pls help

[90gallonreefer]

so I finished setting up my 90G mixed reef yesterday. I noticed the sand has been moving around due to my wave makers. Any tips? I'm fine with the one on the right side which is facing the surface but the one on the left is a problem Here's a picture.

(Yes I know, the sand bed is thin. I can't add anymore sand without removing everything though)

 

[90gallonreefer]

The wave makers have 2 heads each.

 

[ReefRyan]

You could leave everything in the tank and add sand. This is what I did when I was once in your situation. I bought PVC pipe that long enough to get to the bottom and have at least 4 or 5 inches above the water line. The pipe was 2inch PVC and I just add the sand through the pipe. That way the sand was not flying around the tank. It worked out really good for me. (Make sure the powerheards are turned off for this process )