Building a inert substrate underground filter for hardwater shrimp

CLICK Read More to see the pictures!

I am short one bag of gravel from Petco, but I wanted to get the tank cycling asap. 

first I made the PVC Pipe with 1/2 Inch PVC with a 1/2 to 3/4 thread adaptor attached to a nylon 90 degree barb elbow to 3/4 inch threads.  The interior of the pipe is drilled with 1/8" drill bit.

The interior is filled with SeaChem Matrix

pvc isnt straight, oops! 

Next step is make mountains to the top of the pvc pipe.  That's what 20 pounds of gravel looks like

shape the matrix using gravel in the center

covered

All filled up!

Updated 8/17/15:

Click here to see the completed tank