In both fresh and saltwater tanks, ammonia needs to be absolutely zero at all times. This extremely toxic compound is produced constantly by fish and will build up very quickly unless steps are taken to remove it. There are bacteria that will remove ammonia and turn it into non-toxic compounds - this process is called the nitrogen cycle. In freshwater tanks these bacteria live mainly in the filter. In saltwater tanks, they are more likely to be found in live rock or live sand, which are the most natural ways to keep a saltwater tank clean.
The same as in the ocean
yes just add salt!
Yes, Blue Tangs (Paracanthurus hepatus), and all tangs, are exclusively marine(saltwater) fish, and will die in Freshwater within an hour.
It depends on the size of the tank. Ideally most people get 5 gallon buckets of reef salt for ideal tanks.
Damsel fish species include fish like Chromis and Clownfish (like Nemo). They are saltwater fish and if you decide to purchase saltwater fish, please make sure you know how to take care of them. Saltwater tanks must be maintain everyday, especially making sure that water chemistry and temperature is maintained. If you decide to get coral, you must have very strong lighting to simulate sun light. It will get expensive. Budget accordingly. Bigger tanks are easier to maintain than smaller tanks. Water chemistry stays more constant in larger tanks.
I use to own a fish only pet store. The saltwater tanks were a nightmare, constant testing, etc. I would recommend you go to a Pet Shop that has salt water fish, preferrably a one owner store. Make sure the saltwater tanks look good to you, clear water, healthy fish and then ask the owner your questions.
Algae is a result of high levels of phosphates in the tank. A Phos-Ban Reactor is used in mainly saltwater tanks, but can be used in freshwater tanks also.
In freshwater yes. I would not recommend it in saltwater. If it is not in the ocean naturally I would not put it in a saltwater tank. There isn't too much you can't put in freshwater.
In some parts of the US, it is used as a common fertilizer material. Anhydrous ammonia (ammonia with all the water removed) is delivered in pressure tanks to the farmer, who then uses an implement behind a tractor to inject the ammonia about eight to ten inches deep into the soil.
The same way they do today, they took saltwater into tanks while underwater, evaporated out the salt and electrolyzed the oxygen out of it. They also carried tanks of compressed air in the submarine.
It forms a large part of the skeleton of the corals. Fish and other animals in the tank also need it.
You meet the white tanks on mission 20. ;)