Originally Posted by russprimm
but I know I need to get some starter livestock to start with.
When you say starter livestock, i assume you are referring to fish which are capable of surviving the cycling of bacteria. This concept will not exist in the marine aquarium, not as you are used to seeing in freshwater. There is no need to purchase a fish for the sole purpose of establishing the aquarium. You can create a stocking list based on your desires in fish.
Lets start with the basics, and you should see that setting up a marine system is dramatically different from a freshwater system, not only with equipment, but with what you are trying to accomplish from the first 4 to 8 weeks of the aquariums life.
For a 20 gallon tank I would start by adding between 4 and 6 inches of aragonite reef grade sand. This depth of sand bed will allow for denitrification to occur, which is the processing of Nitrate into Nitrogen Gas, which is harmless and leaves the system naturally. Eliminating Nitrates is a concern in the marine hobby, and a goal of zero Nitrate is attainable.
Next, I would add a mix of live rock and dry rock. I personally order my dry rock from Marco Rocks The finest aquarium rock available, base rock, live rock, reef rock, marco rock, reef tank saltwater fish, live corals, Marco rocks, Fiji live rock, Tonga Live rock
, and have had great success with this product. You can see what this looks like on my 180 build thread here: http://www.fishforum.com/saltwater-f...f-build-21979/
I would suggest you order a 25 pounds shipment of dry rock, and then add another 7 or 8 pounds of live rock to "seed" the system. This rock will be the foundation of your filter system, and will create a great amount of stability for the environment, as well as harbor small critters such as copepods and amphipods, which are a natural food source for your fish.
Finally, you will need to pick out a Protein Skimmer. The skimmer will directly REMOVE organic waste (acids) from your system, before the acids have the opportunity to break down into Nitrate. This removal of organics from the water is entirely different than the freshwater concept of biological filtration. It is the removal of organics that allows us to keep alkalinity, calcium, phosphates, and Nitrates at the desired levels for long term marine success. The protein skimmer should be your most expensive purchase and will pay for itself many times over by saving you money on salt mix (for water changes), water supplements (for buffering), and livestock loss (overall stability).
Assuming you want a protein skimmer that hangs on the aquarium, here are a few suggestions.
The Coralife Hang on is effective and capable of handling almost anything you want to do in a 38 gallon tank or smaller: Super Skimmer with Needle Wheel - Up to 65 Gallon | Venturi Models | Protein Skimmers | Aquarium - ThatPetPlace.com
The SeaClone is similar in price and efficiency, but requires more daily tinkering with the water flow: Seaclone Protein Skimmer 100 - 17 3/4 in. high | Venturi Models | Protein Skimmers | Aquarium - ThatPetPlace.com
The Octopus 100 hang on model is just a touch more in price, but is also effective on small sized aquariums, and is much more user friendly. You just plug and go, and it is easy to service: Reef Octopus BH 100 Hang on Back Protein Skimmer - AquaCave
You should allow the live rock and dry rock a couple of weeks to mature in your system prior to adding any livestock. This will allow your copepod and amphipod populations time to spread. After a week or so you can add some small inverts, such as a couple snails and hermit crabs. If you want to add a tiny pinch of flake food every few days during this period, this will be fine. Odds are very good that you will never see an ammonia or nitrite reading when setting up the aquarium as described.
I generally like to wait 4 to 6 weeks prior to adding any fish, which will allow time for the water to entire system to mature. Life will begin to show on your live rock, and the dry rock will quickly seed and become live as well. You will probably have a diatom bloom, which will come and go on its own. You should also be testing for alkalinity and calcium during this time, and modifying your dosing routine to reach the desired levels.
Adding fish is not a critical decision. It can be done within a few short days, or you can wait several weeks. However, especially in smaller tanks, the longer you wait to add fish, the more stable the system will be over the long run.
I strongly suggest you read the entire thread on my 180 build. This will give you a great idea of how the progress of an aquarium environment will be achieved for the first several weeks. There are many other great build threads as well that you should spend time on. After reading this post and reading some build threads, the majority of your questions will be answered and we can focus on specifics.