From what I've read, feed your fry approximately 4 hours after you've fed your rotifers LIVE phyto. This gives your fry the optimum nutritional value from the rotifers. Also, add live phyto to your fry tank I would say for at least the first week. This way your feeding the rotifers in the fry tank while the fry are learning how to hunt them, and you're also eliminating an eventual die off of rotifers. The live phyto does not seem to bother the fry. I'll also use the phyto in the larval tank when it's time to feed brine shrimp. Seems to extend their life span.
I stress LIVE phyto, because in between harvesting rotifers for the fry tank, I will feed the rotifers alternate foods such as non-living phyto or a very blended mixture of yeast, flour, and fish food pellets. Since I get my live phyto from DT, it does cut down on the expense. One drawback from the mixture, it may speed up the need to do a rotifer container water change due to the crud that settles.