Although the Nature Aquarium can be maintained for a long period of time by the trimming and cutting-and-replanting of aquatic plants, it will eventually reach its life limit for reasons such as deteriorated substrate condition. Particularly  when  the  water  flow  within the substrate has been affected as a result of high compaction and broken grains of Aqua Soil or excessive sludge build up, the substrate will not receive adequate oxygen and will become anaerobic. In an anaerobic environment, reduction of nitrate to nitrite and deteriorated water quality caused by decayed organic matters are observed. Such an environment also promotes the growth of algae that prefers anaerobic conditions and leads to poor growth of aquatic plants. These problems are solved by rebuilding the substrate; and this process requires the removal of layout materials and aquatic plants prior to removing the existing substrate layer.

Firstly, you need to pour some tank water into a bucket to transfer the fishes and shrimps from the tank into the bucket. Sometimes it may be difficult to scoop out the fishes and shrimps with a net because some of them hide in the plants or the driftwood used in the layout becomes a hindrance. In this case, it is advised to cut off the bushy stem plants from their base or remove the driftwood from the tank to facilitate the removal of the fishes and shrimps. At this time, be careful not to cause cloudy tank water.

Besides, you need to pay particularly careful attention in the case where a part of the driftwood is buried within the substrate or the runners of the foreground plants twine around the driftwood. The situation in which more than one piece of driftwood have been attached together by epiphytic plants growing on them also requires your particular attention because the driftwood may move unexpectedly in line with the movement of another piece of driftwood which is connected to it, resulting in partial hollowing out of the substrate.

In view of the fact that most of the stones are partially buried within the substrate, the fishes, shrimps and aquatic plants should be removed from the tank before removing the stones in order to facilitate the stone removal work. If epiphytic plants such as ferns and moss are attached to the driftwood which is to be transferred to the new layout, you should cover the driftwood with dampened newspaper and then store it in a plastic bag or plastic wrap. You can keep this driftwood in a cool place for a few days.

If you are planning to make a new layout more than a few days later, you are advised to keep the driftwood together with epiphytic plants on it in the aquarium tank filled with water. If the driftwood is too large to be kept in the tank, you can remove the plants from the driftwood and keep them in the tank water. If the moss has grown too much on the driftwood for the new layout, the moss should be plucked by hand or trimmed with scissors to an adequate level. As long as some portion of it, no matter how little, remains on the driftwood, willow moss will eventually grow large again though  it may take some time. Before placing stones in the new layout, it is advisable to scrub and clean them with a brush