23_3/4x23_3/4x1Exact MERV 13 Plus Carbon AC Furnace Filters 6 Pack fans-ventilation-ducting The result of months of

The result of months of scientific research and trials is Grodan Gro-Blocks Improved with our Advanced Wetting Agent

To further benefit growers

the root zone and surrounding soil

PPF: 1700 µmol/s

23_3/4x23_3/4x1Exact MERV 13 Plus Carbon AC Furnace Filters 6 Pack fans-ventilation-ducting The result of months ofNordic Pure Custom MERV 13 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