Hardscape
Stones and wood, and what they do to your water.
The part most guides skip: some stones are calcareous and slowly push pH and hardness up, which quietly works against a soft-water tank, while most wood leaches tannins that tint the water and nudge pH down. Here's every common stone and wood with its real effect, so you can build a scape that suits the water you want.
Stone
Watch for calcareous stones
Seiryu StoneBlue-grey rock with sharp ridges and bright white calcite veins.
pHHardness
Dragon StoneTan-brown rock full of holes and honeycombed hollows.
pHHardness
Lava RockDark red-black rock, very light for its size and full of tiny pores.
pHHardness- StonePagoda StonePagoda Stone
Layered brown stone with flat stacked tiers, like little pagodas.
pHHardness 
Petrified WoodStone that looks like wood, with grain patterns but rock-hard and heavy.
pHHardness
SlateFlat grey layered stone that splits into thin sheets.
pHHardness- StoneTexas Holey RockTexas Holey Rock
Pale cream stone full of large smooth holes and tunnels.
pHHardness
Wood
Watch for tannins and floating
Spider WoodFine pale branching root wood that splits into thin twisting fingers.
pHHardnessmoderate tanninssoak first
Manzanita WoodSmooth, hard, reddish branching wood with a clean fine taper.
pHHardnesslow tanninssoak first
Mopani WoodHeavy, dense two-tone wood, dark and light, with a sandblasted look.
pHHardnesshigh tanninssinks
Malaysian DriftwoodDense dark brown wood that sinks on its own, gnarled and solid.
pHHardnessmoderate tanninssinks- WoodCholla WoodCholla Wood
Hollow tube of wood full of natural holes, light and honeycombed.
pHHardnessmoderate tanninssoak first
See real pieces before you buy
74 stones, woods and bonsai trees from suppliers, with photos, sizes and what each does to your water.
Picked your stone and wood? The next step is arranging it. See aquascaping design and composition for the rule of thirds, layout shapes and the main styles.