20x20x5 (4 3/8) Honeywell/Lennox Replacement Furnace Filters MERV 8 Pleated Plus Carbon 2 Pack spl_spectrumking This ideal ratio provides higher

This ideal ratio provides higher potassium levels to increase biomass while amplified phosphorous levels promote flower initiation

The Checker is the most popular pH meter in the world with over 1 million meters used since its introduction in 1991

making it difficult for any dark green algae to form

100% Organic microbial exudates (enzymes)

The FULL NOVA WX is e-ballast compatible and is supported by a one-year warranty

20x20x5 (4 3/8) Honeywell/Lennox Replacement Furnace Filters MERV 8 Pleated Plus Carbon 2 Pack spl_spectrumking This ideal ratio provides higherImportant Note: Almost ALL furnace filters have a different "actual size" than the nominal size printed on the air conditioner filter. It's best if you measure your air filter for the EXACT size and compare it to our "Actual Size" and then you can be sure your A C air filter fits! With the 4" and 5" air filters there is a wider variance between the nominal and actual size depending on the manufacturer. We also carry 4 7 8 and 5 1 4 inch depth filters,