Here's a couple of answer I got off another few sites:
The de that low's carry is called pool grade, it would be like feeding your animals ground up glass.
Pool grade DE is Diatomaceous Earth produced for pool filters and it is treated with heat, causing the formerly amorphous silicon dioxide to assume crystalline form. Pool grade DE should never be used for pest control. Swimming pool DE ranges from 60% to 70% free silica!
I'd try and return what you bought, Chicabee.
I bought a couple of small bags from Foy's Pigeon Supply.