new aquarium

Filtration--you probably are getting a wet/dry. These can cause problems, as they trap debris, and this contributes to high nitrates. Of course, regular maintenance is a must, so make sure they show you how to care for the filter (not matter what kind it is).

I'm a big fan of the deep sand beds--3-6 inches of sand not only looks great, and harbors beneficial bacteria, but it makes for happier fish, IME, since many fish prefer sand for burying themselves, etc.

Before you get any fish or inverts--you need to cycle the tank. Either Bio-Spira, or get a few cocktail shrimp from the deli. I am not a fan of using damsels--not only does it hurt the fish but then you are left either stocking around the little buggers or tearing everything apart to catch them and get them out. Several threads here cover cycling.

Once the tank is cycled, you need to pick a centerpiece fish--one that has the personality you want and will fit in your tank as an adult. Then we can help make selections around that fish. Ditto for corals and inverts--they are not all compatible, so if you decide you just must have a trigger, you won't get many corals or inverts that will be safe.

Your choice of tangs will be limited, due to their needs for lots of space and swimming room. A yellow, or a kole tang will be a good choice, and fairly reef safe. However--due to aggression and sensitivity--they shouldn't be the first fish added. Tangs react poorly when water quality fluctuates, and can have serious health problems. Not saying to avoid them, just don't get one until you're comfortable maintaining the tank.

Angelfish--there are lots of kinds, some will outgrow your tank, while pygmy angels like bicolors, flame, coral beauty, potters, etc will be the right size, but some are hard to keep fish. The main problem most people have is getting them to eat, so make sure the fish is eating--actually make them feed it in front of you--before purchasing. Coral beauty angels needs lots of sponge intheir diet, so are not ideal tank mates, even though they are lovely. All angels are prone to picking at coral polyps--they are only moderately reef safe, as individuals vary. some will be fine, others will turn a reef into a buffet.

Clowns are in the same family as damsels-which means they are very territorial. Groups can work out, but only if they start out together and can form a dominant female and her harem (all clowns are inherently male, the dominant fish changes gender). An anemone is NOT needed for happy clowns, and is NOT a good choice for a new aquarium. Feeding and lighting issues aside, these animals live for hundreds of years in the wild, but most die within 2 years in an aquarium. Best advice I've ever heard--by the time you really understand why you shouldn't get an anemone, you'r close to being able to take care of one.

The tank is only one piece--live rock and live sand are great filtration, but you need to know more about your lighting, your heaters, powerheads, etc. Will you be maintaining the tank, or will the store?

Okay--just checking. If the LFS has not already provided with a test kit in your package--you need to buy one.

Live rock won't shorten the length of the cycle--that all depends on the bacteria, and how much you start out with compared to how much ammonia is present. If you get cured live rock, it shouldn't contribute ammonia, while uncured certainly will. Fo r primary filtration, you'll need about 1-2 pounds of live rock per gallon of water--so somewhere about 75-90 pounds or rock, and you can split that 50-50 with base rock and live rock. For live sand--if you look around there are a few places that provide calculators for figuring the volume of snad and converting that to pounds. 100 pounds of play sand should be enough, with a bit to spare. Add 5-10 lbs live sand, and you're good to go.

I'm not a fan of giving numbers of fish based on the tank size or dimensions. The problem is that fish vary, a lot. In a 75, I would say that you could easily have 2-3 fish that were about 7-8 inches, or 1 fish that big and 3-4 smaller fish. But, it depends on the fish--the mandarin dragonets max out at 4-6 inches, but are small--yet your tank, raw, wouldn't support one for a month. That's why I really suggest you look through the stores, and in books, and on the web, and pick fish you think you'd like and might work out, then run it by the crew here. I don't want to pick your fish for you--I don't know what you'd like. I can recommend the pygmy angels I listed above, and look into the many types of clown. There are a wide variety of gobies, wrasses, and basslet that will work in your tank in the right combination.