The solution is oxygen saturated from an air pump combined with porous stones.

They entered the building, whose walls seemed cast of porous, volcanic stone.

Moisture finding its way into porous stone can now cause more damage than it used to.

Filtering through the porous stone, it gathered other chemical elements.

But the frame was the original porous stone used to build the manor.

It is a very porous stone and acts as a giant filter.

Rhynchus's surface here was actually pumice or some other kind of light, porous stone.

A rigid loading cap is then placed on top of the upper porous stone.

The porous stone has absorbed enough water to hold her down.

The greenstone is a soft and porous stone that absorbs water.