It's Only Just Begun
Well, here you are, an excited new aquarist, with a functioning tank and the desire to keep going forward. So, what's next? Aside from expanding your knowledge even further, there will always be maintenance that needs to be done to keep you tank and its inhabitants happy and healthy. Of course, you must feed your inhabitants their required diet, and this can vary from species to species. This may require you purchasing many different food types for your tank. Some fish may relish flake foods, others need fresh cut meaty foods. Again, this is entirely dependant upon what you are caring for. There are two rules of thumb that must be followed with regards to feeding. First, never overfeed. This can lead to poor water conditions, unwanted algae growth and an unhealthy environment. Second, always vary the foods you feed. Just because your clowns love the flake food, does not mean its good to eat every single time. Mix it up with dried, flake, frozen and fresh cut foods. This will greatly improve the health and happiness of your new friends.
You also need to test your water on a regular basis, and perform routine water changes. Typically a 30% water change is need every 2 - 3 weeks, depending of course on the load you have in your tank. If you are unable to do that much water at one time, you can always perform smaller more frequent water changes. Everything is a balance in this hobby, and you just need to find the structure that works well for you. Only understand that this must be done. So, either purchase a plastic tub large enough to mix and churn your new water in, or get some large jugs and purchase R/O water from your local fish store. When replacing water you may need to replace some of the trace elements lost over time. These will differ from system to system. However, you can find a bottle for just about every need you can have, but of course this will differ from person to person. So, determine what you tank requires by reading the requirements for each specimen.
Aside from testing for Ammonia, Nitrites and Nitrates, you need to also monitor you pH levels. This is why I told you to purchase a large bottle. Follow the instructions with the product you purchased and be sure to maintain the pH level at 8.1 - 8.4.
You will also need to have freshwater handy to "top off" your tank. Evaporation is unavoidable. Some tanks experience evaporation less than others. However, they all experience it. The reason you need freshwater is salt does not evaporate. So, as water evaporates from you tank, your salinity will gradually rise over time. This can be very serious if you do not catch it in time. So, it is good practice to check your water with your hydrometer once a week, and add accordingly. Again, I can't stress enough. If you are using tap water, test it first. You need to know what types of minerals and metals you have in the water before adding it to your tank, so you can neutralize them. The best case is to either purchase R/O water, or possibly set up your own R/O unit.
Also, you must check your filtration media such as pads and sponges regularly for cleaning or replacement. This will optimize your water flow, as well as, better your chances for continued success. Remember bio-balls do not need replacing or cleaning. That will defeat their purpose by destroying the established bacteria.
In the future you may wish to expand and strengthen your system and the way you care for it. There are plenty of options for additional equipment. There is way too much to go into great detail here, but I'll try to mention a few. At some point you may wish to acquire a quarantine tank. I'll bet some will argue that this should have been included as an essential in the guide you just read. I can agree to a degree, however I wanted to express what is needed to create one functioning tank. A quarantine tank is not essential, nor is it required. It is however highly recommended and that is why I will mention it here. Quarantines are simply a very basic small second aquarium. They serve a couple of purposes. First, it is a place treat new fish for a couple of weeks before introducing them to your main system. This allows enough time to kill off any parasites that may be on the fish, so it does not infect your established tank. Unfortunately, Ich is an all too common disease in aquarium life. Most aquarist will experience an Ich outbreak at one time or another, and it can be very difficult to treat in a reef tank. By utilizing a quarantine tank with copper based medication, you will greatly reduce your chances of infecting your tank by an outside source. Secondly, if you happen to have an ill fish, you can take it from your main tank and place it in the quarantine for treatment away from everyone else.
Some equipment you should do more research on for improved filtration would be UV Sterilizers and Protein Skimmers. You will find arguments both for and against these pieces of equipment, however the majority will recommend these to you. A UV Sterilizer is a device that uses Ultra Violet light to kill free floating, water-borne bacteria, algae and other microorganisms, which lead to problems and illness within your tank. Some argue that although they do work well, they also kill some of the "good" floating organisms. In my opinion, the good outweighs any bad.
Protein Skimmers are also a debatable topic. However, again the majorities employ Protein Skimmers because they are extremely effective in removing waste from you system. There are a few different Skimming designs, however they all work via foam fractioning. Simply put, bubbles pull floating waste up and out of the skimmer, leaving cleaner water behind. That is extremely simplified and there is much more to it. However, for now that should give you an idea. Again, I feel they are essential, but you should research more and decide. If you do decide to use one, you do not need to put it into service right away. Wait a few months and allow your tank to get established.
One last method of filtration that is quickly growing in popularity is employing a Refugium. As touched on before, a Refugium is simply a section of your system that is free from predators. It can be either above, below, to the side or even hung on the back. Basically, it is a place that you can grow Macro-algae in a safe environment. The benefit is again the best filtration in my opinion, nature taking care of nature. The Macro-algae helps to reduce nitrates within your system, as well as phosphates and ammonia. At the same time, addition of live rock to the Refugium will give you a breeding ground for copepods and amphipods which will eventually find their way into your main tank as food.
As you can probably tell, I could continue on and on about equipment, methods and ideals. I will spare you anymore, after all this was written for the newcomer to gain the know how to begin his or her Saltwater Aquarium. By this point you should have already gained a world of knowledge compared to where you started, and you should have the tools necessary to move forward into the awesome hobby of keeping a marine aquarium. Just remember patience and knowledge are the keys. Plan ahead, do your research and allow FishDB to help you along the way. Good Luck and have fun.