I'm looking for an economical solution for the way I want my tank scaped. It's 4ft x 4ft x 2ft high. I want to create shelves that rise like steps from the front to the back and I was considering using bricks.
Is there any obvious reason a clay brick would be bad for a PT?
I've used red bricks in a few of my tanks to create shelves and walls. I also use them to attach very large rhizome plants and cover them with different types of moss. Bricks are easy to work with because of their uniform shape. Clay bricks should be fairly inert (much like terracotta). The only drawback I can think of would be the amount of water they can displace inside a tank.
Egg crate and PVC is an option depending on what you are trying to accomplish. Bricks add a lot of weight, but they will work. I've used concrete pavers before for similar uses. It might add to your TDS or hardness due to mineral leeching so you may want to keep an eye on that if you have shrimp or other mineral sensitive critters in the tank.