9x13x1 MERV 13 Plus Carbon AC Furnace Filters 6 Pack drying-racks The yellow LED indicator shows

The yellow LED indicator shows CO2 level equal or above 800ppm which means supplemental CO2 is in use

PE and CPE

This blend promotes strong

We use a proprietary blend of minerals in our Cal Mag formula to help boost plant yields in fruiting and flowering plant varieties

When mounted to 5-MSP pump

9x13x1 MERV 13 Plus Carbon AC Furnace Filters 6 Pack drying-racks The yellow LED indicator showsNordic 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