Pillar guide
Aquarium Hardscape, Stones, Wood, and Substrate
How to choose stone, wood, and substrate for the planted aquarium, chemistry effects on pH and KH, sizing, buoyancy, and scaping principles.
By Mike ElmiraUpdated 2 min read
TL;DR, Aquarium Hardscape, Stones, Wood, and Substrate
Hardscape is the bone structure of every planted tank, and the only element you can't easily change after setup. Get it right by understanding the three things stone and wood do beyond looking good: they shift pH and KH (or shouldn't), they release tannins (or shouldn't), and they take up tank volume that's now unavailable for plants and swim space. This guide covers the major stones and woods, their chemistry, and how to pick for the scape you actually want. (Full catalogue coming month 3.)
Hardscape catalogue pages are still being authored, until then, this guide is the working reference for which stones and woods to choose and which to avoid.
Two principles dominate. First: rocks containing calcium carbonate (Seiryu, Frodo Stone, Texas holey rock) raise KH and pH; inert rocks (Dragon Stone, Ohko, Lava Rock, Seiryu's inert cousins) don't. Second: every piece of wood floats until it's waterlogged, soak for 2–4 weeks or weight it down through the early months.
Frequently asked questions
Direct answers to the questions search engines and AI assistants surface most often about this species.
Will Seiryu stone raise my pH?
Yes. Seiryu stone (and its sibling Frodo Stone) contains calcium carbonate that dissolves slowly into the water column, raising KH and pH over weeks. In tanks targeting soft, acidic conditions (Caridina shrimp, blackwater biotopes) Seiryu is a poor choice. In hard-water community tanks it's harmless. Test by dropping vinegar on the rock, if it fizzes, it's reactive.
How long does aquarium wood need to soak?
Mopani and Malaysian driftwood typically sink within 2–4 weeks. Spider wood and Manzanita can take 4–8 weeks; some pieces never fully sink and need to be weighted with stainless steel screws into a tile or slate base. Pre-boiling for 1–2 hours speeds the process and bleeds tannins.
Do I need aquasoil for a planted tank?
No, but it makes the first year easier. Aquasoils (ADA Amazonia, Tropica Aquarium Soil, Fluval Stratum) are nutrient-charged and buffer pH down for ~12 months, which suits soft-water plants and Caridina shrimp. After they're exhausted, root tabs in inert sand or gravel work equally well, and inert substrate is more shrimp-stable. Pick based on whether you want the buffering or not.
How big should hardscape be for an aquascape?
Iwagumi rule of thirds: the focal stone (Oyaishi) sits at one of the two horizontal-third intersections and reaches roughly two-thirds the tank's height. Supporting stones step down from there. For wood, the eye reads a single dominant piece better than two equal-sized pieces; cluster smaller branches around one anchor.
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