I would skip the rotifers, and feed brine that is enriched with Dans Feed. You can purchase it at seahorsesource.com. With my southern erectus, I would feed two day old brine, enriched with Dan's feed for 24 hours, and changing the water every 12 hours and re-enriching.
Left over brine should be removed. Feeding 5 times a day is best, IMO. Keep the tanks clean. Siphon waste off the bottom as often as you can.