Zandor does not use rapid rooters. He uses peat pellets for seedlings, and Z clones with an aero-unit.

I use rapid rooters for seedlings, and rockwool for clones.
The rapid rooters are excellent for any type of growing method...It is an organic starter...that is all. It is tree bark and gypsum.

Just put the rapid rooter in a netpot and use hydroton expanded clay pellets to backfill around it.

It is in fact an ideal starter. I was looking for an alternative to peat pellets and rockwool when I came across rapid rooters, and will not effect your ph in hydro...peace latewood