Before the Flood
So, now everything should be in place and ready to be filled. The next step would be to add the substrate. Regardless of what you choose to add to the system, with the exception of live sand, you can go ahead and add now. However, it is definitely advisable to rinse the substrate before hand. Most of the sand and crushed coral will be covered in fine dust and bits of trash. It won't harm your system, but it will take a considerable time longer for your tank to clear up after you add water. There are a few ways to do this, one being a colander. This method will really only work for crushed coral being that sand would fall through. Keep filling it up and running water through it. Once the water starts running clear add it to the tank. It is a slow process but it works very well. Another way, which will also work for sand, is to fill a 5-gallon bucket halfway with substrate. Then, run water continuously into the container via a hose. Once the bucket fills, it will begin to overflow and carry any free-floating trash with it. While occasionally stirring the substrate, allow the water to keep running until it overflows clear. Then drain and add to your tank. Continue adding until your desired depth is reached. If you are not sure, then start with a depth of 3 inches. This will be suitable for most setups. If you know you will have "burrowing" animals, then you should determine their requirements. You can always add more at a later time.
You have now accomplished the bare minimum to be able to fill the tank with water. However, here are some considerations. Are you going to be adding rock to the system right away? Can you afford to purchase a good bit of live rock right now? Do you have a plan for your rockwork? If you are not going to have any rock, which is fairly rare, then skip the next part. However, if you are like most people, you will want some for at least décor. So, now we should discuss the what, why, when and how we use rock in our system.
As far as choices for rock in our aquarium, you can go with live rock, base rock or artificial. Live rock being rock that has been kept in an environment such that it already hosts the beneficial bacteria and microorganisms we desire. Base rock is dry rock, void of any life. Artificial is well simply any rock that is "man made" as apposed to rock collected from the ocean. Regardless of what you place in your tank, it will eventually become "alive" with life. However, the benefit of initially placing existing live rock into your system is it will greatly speed up the cycle time of your tank.
So, why should you even use rock in your system? Well, it serves a few functions. First of all, it simply creates a more natural look. Second, depending on the type of fish you choose to keep will dictate how much and in what way you will implement the rockwork. Larger fish or extremely active swimmers will need less rockwork to feel comfortable. They may not require any, or possibly a large cave or ledge where they can reside. Smaller fish, especially those that live around the reef, need many rocky places where they can dart in and out of and hide to feel secure. Some require at least one piece they can burrow under to create their home. All, of the individual specimen requirements can be found in our database. The third aspect is certainly worth its weight in rock. If you choose to purchase "live rock", you will be adding a greater dimension to your overall filtration system. As with "live sand", live rock harbors beneficial bacteria and invertebrates, which not only help to break down waste and improve water quality, but also provides a food source for many fish that you may keep.
If you are planning to do a lot of aquascaping, it is best to do a lot of your "base" work before you have filled the aquarium. You may ask, if live rock is so beneficial, then why not add only that? Easy, its will be under all of your rockwork. So, any life may die off due to the lack of light and circulation. As stated before, the exposed areas will eventually become alive and prove beneficial. So, save the money and build up from cheap base rock. Save the "good stuff" for the main construction of your rockwork.
So, beginning your construction is much like planning a very abstract home. You're free to do as you please. Be creative and have fun, this is where the whole look and feel of your display begins. This entails buying base rock and placing it in the positions where you want to build your reef up from. As I said, be creative, but I must give some guidelines. First of all, rockwork is terrific for decoration, hiding places and biological filtration. However, it can be a real hindrance on water circulation. The way to build and still maintain a good water flow through all areas of the tank it to maximize areas between rocks. This means you do not want to pile all of the rocks on top of each other in one big mound. Stack you pieces so that there are throughways, caves and channels. Your fish will love it and you're less likely to have dead spots. Also, a common mistake people do is build-up their rocks directly against their back glass. This may leave more room out front, however it will certainly create dead spots along the back bottom of the tank. So, try to leave some room back there for water to travel. It does not have to be much. Just an inch will allow water to freely pass behind the rocks and keep the water circulating. Some even choose to place PVC pipes behind the rockwork to aid in circulation. They drill small holes all along the pipe and attach it to a small circulation pump, or to one of the returns. Some run a pipe directly along the top back of the glass with holes shooting straight down along the glass. Obviously there are many scenarios and many solutions. It is really up to your personal preference combined with the layout of your tank.
Even more important then maximizing water circulation is the stability of the rockwork itself. I have witnessed and been a victim of poor "structural engineering". I had the entire right side of a 75-gallon reef tank collapse by the removal of a rock during maintenance. As a result, I had to rebuild then entire right side. That soon led to the collapse of the left side while I was working. I will admit, the problem was in the construction. Although the tank had existed for over a year's time with no problems, all it took was the removal of a rock near the top to bring down the wall. So, taking what I learned the hard way, I hope I can help you from meeting the same fate. What went wrong? Well, first of all, I had all of my rocks sitting on top of 5 inches of substrate. Why is that a problem? Well, over the year many animals burrowed below the bottom rocks. As the sand shifted and was pushed out from below, the rocks began to slowly lower and shift. Well, of course, from the beginning of the tank all the way until the "great fall" the makeup of the structure was slowly changed and, not to mention, I was adding more rock on top as my tank grew. As rocks began to sink, the ones above had to follow. But, of course, this happened in different areas at different times. So, eventually the structural integrity was compromised and all it took was the moment I pulled one out. So, how can you prevent this? The best way is to cut 1" PVC pipes into sections a little shorter than the depth you plan your substrate to be. Place these between your base rock and the glass bottom assuring that the rock cannot ever settle further down. This will also ensure that any burrowing animals can be safe from a collapse. So, once you have established your base, you can begin to build up from there with your remaining rock. As you go, remember to push the rocks downward and rock back and forth. You want them to fit together snug, so there is no chance of being knocked over. Remember to leave through ways and caves. You are getting close now.