16_1/4x21_1/2x1 Exact MERV 7 Plus Carbon AC Furnace Filters 6 Pack grow-system/-trays/-reservoirs The design consideration for the

The design consideration for the HI12943 is ideal for pH measurements in soils and hydroponics growing media including rockwool

That means that when properly installed no light will penetrate the ducting and disrupt your plants' lights out schedule

Extremely energy efficient

• Secondary dewaxing

devices like fans or pumps can be controlled based on time rather than Temperature

16_1/4x21_1/2x1 Exact MERV 7 Plus Carbon AC Furnace Filters 6 Pack grow-system/-trays/-reservoirs The design consideration for 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