Lynn,
Yes, you are adding the liverock for filtration, but you want it to look cool too! BTW I stole Tanu's idea too, but it wouldn't fit in the picture (it is all the way to the right in the tank) and it hasn't had enough time to look anywhere near as cool as Tanu's.
BTW- that's 270 Lbs of LR, which is 1.5 lbs/gal. If I had simply stacked it it would not have reached 1/2 as high in the tank.
The PVC makes the rock seem more like a reef, and allows me to use ty-wraps (wire ties) to anchor certain pieces to the frame. Having rock high up in the tank allows me to place certain corals high up, right under the lights.
The PVC fram allows goo water movement and swimming room behind and under the rock. My tang loves it!
The kid is one of the few things I like more than my reef! Him and my wife. He is 13 months, and is leaving no stone unturned in our house right now. I built the stand up high so that it would be difficult for him to put things in it
We think that Rebecca (My wife) is pregnant, so I am going to have to re-focus on child proofing the fish room! That is something to think about if you have grandkids (or may in the future)
Ernie