Peat pellets in substrate??

[mummyof2]

I got a package of peat pellets by plantation products at Walmart. My idea was to break them into 1/4 s and place them in the substrate under my plants as a better medium for them to grow. Are they safe?? There are no fertilizers listed on the package. I have a 70 gallon planted tank with rainbows, mollies, angels, a loach, 2 plecos and a peacock eel I just don't want to poison them in my quest for the perfect planted tank!! My ph is also around 7.4 and by adding the peat even if it leeches tannins I would welcome a ph drop of .1 or .2. So any opinions or experience???
Thanks,
Barbara