Anthony, I think I found a possible solution. As you can see in the previous pictures, I have a small hole drilled in the top of both 90 degree elbows coming off the back of the tank. I originally had a 3-4” piece of airline tubing inserted in each of those holes for air intake. Well, I just took a much long piece of airline tubing (approximately 3 ft. the length of the straight piece of pvc in which the water vertically drops) and fed the tubing most of the way down inside the pipe. For some reason, this made a huge difference in the noise. Im not sure if it has to do with the air intake or introducing friction to the waterfall inside the pipe. Either way, I can hear myself think and now when Im on the phone, everyone doesn’t think Im using the bathroom, lol. Hope this helps.
Oh, I also wanted to explain the blue sticky-tack. I am using it to seal around the airline as I test run this for a bit. Im not sure if it makes any difference so I will remove it and see how that effects the noise.