13x25x1 MERV 13 AC Furnace Filters 12 Pack Hydroponics and no off-gassing to harm

and no off-gassing to harm plants

Optimal air to water ratio Sterile and safe around children and pets

and within seconds the meter recognizes the calibration solution and calibrates itself

up to and including the day of harvest

Can be used with all propagation media and growing systems that are used for hydroponic production

13x25x1 MERV 13 AC Furnace Filters 12 Pack Hydroponics and no off-gassing to harmNordic Pure MERV 13 Pleated AC Furnace Air Filters provide exceptional filtration for both home and commercial environments. Each time air passes through a Nordic Pure pleated furnace air filter, lint, dust, pollen, bacteria, pet dander, dust mites, mold spores, smoke particles, virus carriers, coughs and sneezes, smog, allergens and other contaminants are removed. MERV 13 furnace filters are comparable to HVAC filters with the rating of MPR 2200