17x25x1 MERV 7 Plus Carbon AC Furnace Filters 6 Pack coco-cubes This is one of the

This is one of the heaviest blends offered by Four Seasons and requires feeding throughout the entire growing season for best results

Features: Low frequency

factory tested

Easily mixes tanks from 50-500 gallons

CalCarb - Natural Plant Performance Enhancement Boosts Photosynthesis Both calcium and carbon are critical to plant development

17x25x1 MERV 7 Plus Carbon AC Furnace Filters 6 Pack coco-cubes This is one of theNordic Pure Custom MERV 7 Plus Carbon air filters are made based on the actual measurements so be sure to measure your current filter to get the EXACT dimensions before ordering. As with all Nordic Pure filters, the effective life of your filter depends on the environment in which you live. We recommend changing 1 and 2 filters every 30 90 days. Our 4, 5 and 6 inch thick filters could last up to 6 months. EXACT MEASUREMENT: Furnace and air condition