20x21_1/2x1 Exact MERV 10 Plus Carbon AC Furnace Filters 6 Pack Water Pumps & Irrigation Supplies Hanna's Buffer solutions are made

Hanna's Buffer solutions are made from established formulas and are standardized with a pH meter that is calibrated to NBS/NIST primary standard buffer solutions

The CubeCap deprives the cube of its light by reflecting it back up towards the plant and away from the top of the block

• Contains beneficial photosynthetic microorganisms

Efficient integrated flange for 8" ducting

The built-in temperature sensor ensures every reading is adjusted for environmental changes

20x21_1/2x1 Exact MERV 10 Plus Carbon AC Furnace Filters 6 Pack Water Pumps & Irrigation Supplies Hanna's Buffer solutions are madeNordic 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