Hey PT. I use the food grade simply because it's what we have for us. Perhaps the pool grade would be fine for fire ants though. My husband HATES them and would douse them all with gasoline (a VERY quick method of killing a mound) but I won't let him because I don't like that in my yard. Although it's been said that the gas vapors just dissipate very quickly. Still--it stinks and DE is safe if my pets walk through it.
Samala, Renee -------Original Message------- Are you using 'food grade' DE or pool/aquarium grade DE?