Hello there and welcome to the forum. Here are some tips on getting your new 20 gal tank up and running.
First off... you need LOTS and LOTS of patience in starting a tank up. This is crucial. Most people set up their tanks and withing a few days, they are adding fish and inverts, before the tank has cycled.
I have a 29 gal tank that has been set up for about a year now, and maybe telling you what I did and should have done will help.
First, put about 1.5-2 inches of LS in the bottom. There is a whole argument on what kind and the coarsness of it, but found that probably your best bet is to get the fine granular kind and not coarse. It's easier to keep clean and detris and excess food won't get caught in the holes as easily either.
Next, put about 1.5 lbs of LR per gallon size of your tank. I would say you would be safe putting in 13-15 lbs of LR in.
I would definately get a really good heater and set the temperature of the water between 76-79 degrees Far.
When adding the water, I would STRONGLY RECOMMEND using RO/DI water from your LFS, unless you plan on purchasing a kit. Otherwise you will probably have an algae problem down the road with high phosphates in your tap water, not to mention all the other impurities tap water has. When adding the salt, Ususally the LFS can add it for you and tell them you want the SG to be around 1.022-1.026.
When adding the water. I would put the LS in the bottom 1st, then add the water, then add the LR after the water is in. When pouring the water in, use a plate or put plastic down on the sand, otherwise you will stir up your sand so much and have a mess like I did. lol It took about 3 weeks before my sand settled and had to clean my filter out about 1-2 times a day.
I would get a filter set up with carbon and foam. I have an AquaClear 200 that does great. Also, I would recommend getting a protien skimmer in the future as well. I have a SeaClone 150.
Lighting.... This is another argumentative debate that I have seen in this forum. It really depends on your budget and what you want in your tank. If you plan on having a reef tank, you will need stronger lighting. You can go Power Compacts, which is usually the cheapest route for stronger lighting, or you can go with VHO or metal halides. I have a regular flourescent light right now due to budget constrants, but do not have any coral in my tank as of yet. I plan on getting one of those lunar light PC set ups so I can have light all day long.
The next thing you will need is a powerhead. I have a maxi-jet 900 that does just fine for my tank.
Once you get the water in the tank and everything turned on, I would add 1 or 2 raw cocktail shrimp to the tank. Then, LET THE TANK CYCLE. I would not even bother taking any measurement readings on the ammonia, nitrite or nitrate levels for at least 2 weeks. Once 2 weeks has passed, then I would take a reading to those levels. Take the cocktail out and then once the levels are at 0, then you can add a clean up crew, and then after about a week or 2 after that, you can add 1 fish at a time and do so every couple of weeks there after.
Word of caution.....I STRONGLY recommend putting each fish in a quarantine tank for no less than 6 weeks and treat it with Cupramine. Do not add this to your main tank, because it will kill any inverts and probably will never really go away and you will have a heck of a time keeping inverts in your tank. I did not do this and had a heck of a time getting the ich out of my main tank (took almost 6 months). Keep the copper levels in check and do not add any inverts to your quarantine tank. This is just My opinion though on this part. Most others in here will probably agree with me though.
I would not add any corals or anemone for a long while,until your tank is well established. I know its hard to have patience on this, but if you start adding everything at once or before the tank really has had a chance to get established, you will most likely end up with a tank full of dead stuffs
:nope: I hope this helps you out some and good luck.
Sheppie