2'' of 2-3in rocks below the PVC pipes (slits facing down) and then 18'' of 3/4 pea gravels above them
OR
2'' of 2-3in rocks below the PVC pipes (slits facing down), then 1 layer (8'' height) of aquablocks above the PVC grid (2-3in rocks around the aquablox) and then fill 10'' pea gravels.
i'm sitting here thinking , if your pvc is 2" off the floor of the bog this is where any debris will build up and there will be no way to flush it out, so both options don't work.
In a minimalist bog / peastone bog, which i do have one . it's piping is like a trident with vent /waste pipes on the ends that come up to the surface of the bog for flushing out waste later. The ends of the verticals will have screw on end caps to each pipe. 2" pvc . This sits on a second piece of epdm with the slits and pvc slits facing
up. this is so that the main liner doesn't have constant abuse from the pumps. Then i would stack 4" of 2-3 river rock along side and over the pipes making a flat surface burying the pipes. Then a 16" layer of 1" or 3/4 river rock. I would avoid any plants that have very deep roots. This will help your pipes to stay open and not fill up with roots.
In a MATRIX bog / which i do have one . YOU HAVE A TRENCH within the bottom of the bog that runs end to end . place a centipede. down the angled trench away from the Then a 16" layer of 3/4 river rock. I would avoid any plants that have very deep roots. This will help your pipes to stay open and not fill up with roots.