18x27x1 MERV 10 Plus Carbon AC Furnace Filters 6 Pack Environmental Controllers if one of the many

if one of the many essential trace elements is deficient in the soil

Can be used as a bulk media ingredient or in hydroponic and soilless applications

#4 Perlite (1/3" - 3/4" granules)

Individual glasses can be purchased separately

Prefilter: Included

18x27x1 MERV 10 Plus Carbon AC Furnace Filters 6 Pack Environmental Controllers if one of the manyNordic Pure pleated AC air filters are made of electrostatically charged synthetic materials that attract and capture most airborne particulates in your home or office. Each time air passes through a Nordic Pure pleated furnace filter, lint, household dust, pollen, dust mites, pet dander, baking flour, mold spores and other contaminants are removed. Our filter media prevents the growth of bacteria or mold, resulting in a much healthier living space.