Peat (sphagnum moss)

Peat (sphagnum moss). Peat is a controversial additive to the lower layer of the substrate. Peat fibers are polar, that is, with positive and negative sites and with vast surface area and highly porous structure, many qualities to make it a desirable addition to a fresh substrate, which may be lacking in humus, especially during the first six months of the aquarium's career. But peat will leach humic substances into the water, and slowly peat will break down and rot. Unless you've poured boiling water over it, dry peat will be too buoyant at first and will spread its fibers throughout the water. The best peat for substrates will be the "spent" peat from a water-softening peat bucket, which will have neutralized some of its acidity by adsorbing calcium and magnesium ions.