Afternoon,
I've had my first marine aquarium for about 3 months now. (it was a birthday gift to my girlfriend, she gets to look and I get to work). Really enjoying myself with it though. I have done freshwater before, but the difference between the two is like the difference between taking care of a cat and a baby.
I have a 75 gallon display with 85 lbs of rock. Using a 40 gallon breeder as a sump, powered by a mag 9 and a lifereef siphon overflow. Octopus Extreme XS160 skimmer, 6xT5HO fixture, Fluval 305 used to run carbon and plumbed into the sump. About a 15 gallon refugium with a 5" deep sand bed and a ball of chaeto. 2 Hydor Koralia Evo 750's on a wavemaker.
So far I'm stocked with blue tang, a sailfin tang (both are about 3" and will be donated to the local aquarium when they outgrow the tank, the girlfriend just had to have them), 2 banggai cardinals, 2 lyretail anthias, a gold stripe maroon clown and his green bubble tip, a lawnmower blenny, a bluegreen chromis, a coral banded shrimp, a fighting conch, assorted hermits & snails. Corals include a candy cane, a large green hammer, a florida ricordea, a finger leather, some green hairy mushrooms, a sun polyp, and a yellow gorgonian (rescued from a bad LFS, I may donate it to a better store or the aquarium if it declines in my care, so far it's doing well though). Also have a Deresa clam.
I keep my specific gravity at 1.025, temperature at 78, calcium at 420 and alk at 9. Phosphates and nitrates are about 0.1. I perform a 15 gallon water change once a week, which limits the amount I have to supplement to the bare minimum.
Sorry that was a little long winded. If anyone has any suggestions or advice feel free to reply.