Used by itself or mixed into other mediums, Perlite is one of the best hydroponic growing aggregates around. Perlite is commonly used with Vermiculite (a 50/50 mix) to create the perfect balance of oxygen and moisture for your plant's roots. It is mainly added into a grow medium to enhance drainage and aeration. It is chemically inert. It has a neutral pH.
It does not degrade or cause any chemical reactions with nutrient formula's.
Water trapped in the structure of the material vaporises and escapes, and this causes the expansion of the material to 13 times its original volume.
The drawback to Perlite is that it doesn't retain water well which means that it will dry out quickly between watering's if used alone. The dust from Perlite is bad for your health so you should wear a dust mask when handling it.