Second layer of 4"

Now all the pipes are in and connected. I have 12 - 4" in the first layer, 11 in the second. The two 6" that make up the manifolds are about 20 foot each under ground, and all the 4" total is just about 520 liner feet of pipe. I needed 450 liner foot of pipe or better for this size greenhouse so I have about 14% extra. I'll show the math on how I figured that out later. Next I'll add 18 inches of fill on top of those pipes. Spread and compact it with the excavator every time I dump a load.