
When I use my combo PH/Fertility meter to compare the fertility of my Mexican Bat Guano (3 tab/per 1 gal water) and Miricle Grow mixed in water, the Miricle Grow mixter shows I'm in a good fertility range while the Bat Guano says the mixture is not fertile at all- The Bat Guano tea is PH balanced - but it's not registering as fertile. Why?