Rock wall having fast colour for aquarium - use

摘要

The process involves the correct proportions of materials, e.g. 2 kg sand, 1/2 kg cement, and 2 ozs red cement oxide (sic). The latter ingredient determines the fast colour. Spec. the wall, after construction, must stand for 3 days in running water, or 15 days in still water, so that the cement takes effect. The wall is then ready for installation in the aquarium.