Typically $15-20 / gallon is a good estimate
- Filtration systems?
Really depends, but most use either canisters, hang-on-tank, fuges, or wet/dry
- Keeping salinity,pH, temp. constant?
Adding fresh water will keep the salanity constant much fluctuations are not to much to be concerned about. pH stays normal through regular water changes and a heater will keep the temp constant.
- Protein skimmers? (Is there another method? If so is it more/less affective?)
Protein skimmers are considered by most to be a necessity. Personally, I think it depends on how much and often you feed. Most new aquarists do overfeed so a skimmer should be on your list. Coralife and Aqua C Remoras are two good ones. Another method to skimming is the use of mangroves. They remove the nitrates and phosphates in the water and also help keep unwanted algae at bay.
- Live rocks vs. Sand vs. Something else (Mix?)
Not really sure the vs. LR
is always a great idea. Sand is much better than crushed coral.
- Sizes of filters/skimmers/heaters?
Depends on the tank size, but if you do go with a 55, then a 10 gallon tank would suffice for a sump, fuge, or wet/dry. Typically, your sump size should be 1/5 of the tank size and water turn over should be 10-20 times the tanks volume per hour. If you're thinking a HOT, then I'd suggest two penguin 400 biowheels. a 200-300 watt heater would be big enough.
Again this depends on what you eventually want your tank to be - Fish Only, Fish Only With Live Rock, or Reef. FO
really don't need any special lighting. Standard compact flourescents will do. Reefs are really a much different story and I would suggest waiting on inverts until you get your fet wet. I use two 4 bulb coralifes on my 55 with FO
and it's plenty.
- Levels tests? Log books?
Once established, testing is, IMHO
, for a FO
is a waste of time and money; however you must perform regular water changes. For reef, I'd suggest a nitrate kit and pH kit / alkalinity kit. You could get a calcium kit, but if you add too much calcium, it will just precipitate out - no harm no foul.
Suggest you do a lot of reading and research on this hobby before getting started. It will save you many headaches and lots of money. Good luck!