How much do I need for my tank?
Plan on roughly 1–1.5 kg of stone per gallon for a structured layout, less for minimal Iwagumi styles. Every listing shows real weight and dimensions so you can add it up.
Does it need cleaning before it goes in?
Everything is pre-washed, but give it a rinse and a stiff-brush scrub anyway — never soap. Wood usually needs a soak before it sinks.