I don't feed my Cephs bugs, they catch a few on there own. So hopefully someone else can chime in.
I do add fertilizers to the watering trays/flood systems/ect. Starting with 0 TDS water I add ferts to bring it up around 50/100/200 depending on the system. If your not using RO water I would be really careful with this, 50 TDS tap water is a very different animal than the 50 TDS RO water with ferts added.