I was never successful keeping pipefish with seahorses and have not attempted again for over 10 yrs. I wouldn't try it unless I could buy captive bred pipefish to go with captive bred seahorses. I believe it is most likely the fact seahorses don't do well when exposed to pathogens they haven't grown up with and wildcaught pipefish seem to give them that new exposure. Even other fish can be the source of the problem many times. It partially will depend on the individual seahorse, as seahorses like people, have varying degrees of susceptibility to disease and illness. You DON'T, however, know that your seahorse(s) capabilities are, often until it's too late.
One reason I had so many tanks for so many years was of my fondness for tangs. I have had many and I've never found any that I would put in a seahorse tank. Too much possibility of aggressive movements if not actual aggression and that causes stress in the seahorses that leads to disease or pathogen outbreak. That particular tang should have at least a 60g tank and that's without considering what tankmates it has.
No seahorse will do well with once a day feeding with a refugium IMO.
First of all, most pods are of little value to a seahorse because they are too small and only an inordinate amount of them would suffice at best. Also, most seahorses beyond several months of age will have an interest in feeding off them.
The exception here is that seahorses will definitely feed on amphipods as they are a sufficiently large enough pod. However, they would very quickly decimate the pod population of even a VERY LARGE refugium.
My personal feeding regime has evolved over 17 yrs to feeding Hikari mysis four times a day, and once a week feeding of enriched live adult artemia. I've found that feeding only what they can eat in about 15-20 minutes max, and feeding more often, leaves them more nourished and healthier to deal with potential problems. It also suits their natural feeding better as seahorses have no stomach, only a rudimentary digestive tract, and are day long grazers for food. Excessive food all at once means pushing the food through the tract too fast for adsorption of sufficient nutrition.
I can't comment on Nutramar Ova as I've never used it.