You should know that with seahorses, is best to have live food. Some seahorses will take frozen food, but live food is always best. Dwarf seahorses will eat newly hatched brine shrimp, and will readily breed in captivity.
Larger seahorses cannot live on brine shrimp very long and will slowly starve to death. It would be best to feed them copepods, mysis shrimp, mysid shrimp or scuds. Some people recommend dipping their food in vitamins / HUFAs (Highly Unsaturated Fatty Acids), such a Vibrance.
They need "hitching posts" to be able rest on. For hitching posts, you can use Gorgonians, sea fans, live plants like caulerpa, halimeda, merman shaving brushes, etc. Most anything that they can wrap their tails around will work.
The reason for slow moving water is for feeding purposes. Seahorses do not move very fast, and need to be able to snatch their food as it floats by. The filtration system can be turned off during feeding times helping catch their dinner. Other fish in the tank are usually not recommended since they can move faster, and the seahorse cannot compete with them for food. Pipefish are well suited to keep with seahorses, and should be ok.
Seahorses should be feed atleast twice a day, and will move around the tank looking for food all day long.
If taken care of, you will find these to be one of the most enjoyable tank inhabitants that you can have. Larger seahorses can be hand fed frozen foods on occasion, and you will find that the females are more apt to eat directly from your fingers than the males.
If you did not know, the female deposits her eggs in the male, he fertilizes, incubates them and delivers the young. It is really neat watching him deliver the young. They look like a minature copy of their parents only a little skinnier.
If you have not had seahorses before, make sure you do some reading first, find/create a good food supply and you and your new friends will be happy. I wish you the best of luck in you new venture.