Choosing and Setting up a Marine Aquarium

The Startup Phase

1. Siting

First and foremost site the aquarium where you know you are not going to want or need to move it in 6 months' time!
Moving any aquarium means emptying it of water, moving a large aquarium will mean a complete strip- down.

2. Rockwork and Sand

Now add any base rockwork, if used, preferably on top of a perspex/ plexiglass layer covering the clean glass aquarium base. Some use styropor. Any plastics should not contain plasticisers, which is why all piping should be made from U-PVC and glued with Tangit. Plasticisers also have an adverse effect on us.
A thin layer of washed aragonite, coral sand or 'live' sand should be added now, if used. Rocks should be lying on the base for stability and not on top of the sand. Some fish such as wrasses bury themselves, so at least part of the base covering should be deeper for them. This can be constructed by gluing some of the rockwork together to make a separate deeper area.
Living rock can be put on top of the lower rock layers. It is expensive, so would be inadvisable to use for the complete rockwork. Make areas where fish can swim in and out of, and hide themselves. they will then feel more secure.

3. Pumps

Fix the flow pump(s) in position. If you have a sump, connect the piping to the return pump. Open all valves fully in the tank/ sump recirculation system. Water pumps should never be run dry for more than a few moments, so don't plug them in before you have added the-

4. Water

If you already have seawater matured and ready, now is the time to add this, you can allow the water to go over into the sump and switch on the flow and return pumps. Also necessary if starting with 'live' rock or sand.

If you are adding fresh water, preferably reverse osmosis water, add this to a level where the flow pumps just function and no higher. Then add the marine salt, maybe a little less than you will finally need. Switch on the flow and watch the salt dissolve. You can then make the final adjustments later.

5. Waiting Time

Now comes a period of waiting. If you have used live rock you may observe some changes. It may also smell, since it is generally shipped dry and some organisms deep in the crevices may have died. This will pass. Check the water parameters regularly, in particular the density, pH, KH, Nitrite and Nitrate to see that everything is working as it should. An initial Nitrite spike should disappear.
After a few weeks, and there might be an algal bloom phase to go through first, then you can consider you first purchases. Whatever you do, do not add hardy but aggressive fishes now, the first in will be the boss fish and possibly terrorise any newcomers.