I'm not sure what you actually mean here!
But I take it you are referring to the little dried, compressed disks usually branded as "Jiffy Peat Pellets" for horticulture.
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If so, I use them all the time as they are excellent for annual sp. breeding as they are much more manageable than peat moss in its raw state.
If your breeding annuals just pop one in a jam jar or similar, let it sink and expand and then discard the brown tannin water, refill and let stand, again discard the tannin stained water. On the third refill, let the peat settle to the bottom of the jar and then carefully add to the breeding aquaria.
There is a similar product that you can also use called
Coir but I find this much to harsh as its a lot more coarse and fibred than the peat.
Regards
C