Adding top layer of sand - some concerns...

I want to try the DE and the bombs, want to make sure I get the right product:

Can someone please reccommend where I can find the proper DE? Is there a certain type or brand of DE I am looking for? Is it available at big chain stores like Home Depot or Lowe's, or will I only find it at a grow shop?

Same questions for the bombs - can someone please tell me if there is a certain brand or type of bomb I need? Are the bombs available at the big chain stores, or grow shop only? Also, can you use them in the middle of a grow, or do you need to have an empty room?

I want to apply the DE and drop a few bombs ASAP, just not sure exactly what I need.

Any help would be greatly appreciated. I am about two weeks into flowering and don't want these little bastards to ruin the buds I have worked so hard on.

Thanks again,

The Captain

i just added a layer of sand to my veg plants that didnt have root aphids as a preventative... The flower room is full on infestation, I just og biowar'd, was thinkin bout adding a layer of sand to the flower plants too, but they arent in smart pots like the veg so i dont know if that will do anything, aphids mite just crawl up through the bottom holes... They are 4 weeks in flower so pesticides are a no no.