17_1/4x29_1/4x1 Exact MERV 10 Plus Carbon AC Furnace Filters 6 Pack PH/EC/TDS Meters and Solutions Simple calibration

Simple calibration

New and improved wetting agent and hydrophilic technology greatly enhances the water characteristics of Grodan Gro-Blocks Improved giving even better water distribution over the height of the block

Corrosion-resistant nylon housing

It is virtually impossible to over-water plants with this formula

17_1/4x29_1/4x1 Exact MERV 10 Plus Carbon AC Furnace Filters 6 Pack PH/EC/TDS Meters and Solutions Simple calibrationNordic Pure Custom MERV 10 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