act like a child it's just that I've spent a lot of time on the sand_fall and spent a good bit of money also. This is what I used and how I built it ...
(1) 3"
pvc pipe ran up back of 4"
pvc pipe used for structure of rocks
(2) top elbow for sand to collect to go back down
(3) cut a slot out of 1 side of bottom of the 3"
pvc pipe for sand to collect
(4) used a 4"
pvc pipe to add rocks too as my main site
(5) cut hole into elbow in top of pipe to run a airstone down into it
(6) used only GE Silicone I
(7) put a bowl on the outside bottom for sand to fall into and go back up the pipe
(8) cut hole into 4"
pvc at top and bottom for elbow to go through
(9) placed 3"
pvc pipe so slot at bottom would be at the bottom of 4" pipe
Going to do 50% water change and add carbon Thanks Mike