A word of warning: starting a marine tank cause a serious change in human behavioural patterns - looking dreamy eyed at your tank for hours on end; phoning your loved ones (or anyone!) in the middle of the night to tell them about a new polyp, worm, glowing thingy about 1mm long, ... which you have just discovered; not buying new clothes, furniture etc. because your tank REALLY needs that new light, filter, ROCK, etc.... Oh well, maybe you won't get hooked so badly.
Whilst gathering your information, you must THINK. Is it logical, does it agree with what other books say, or with the views of "experts"? You must also get as many recommendations as you can, and then try to decide what is right FOR YOUR PARTICULAR SITUATION. Even some of the most notable "experts" on the net, some even with PhD's, can't agree on "what is right" all the time. They do tend to agree on the basics, though, so if you get some "way off" advice, you should be wary.
Deciding on the TYPE of set-up
The general statement that "a Fish Only system is easier to keep" (or that "inverts are a lot harder to keep") is very misleading, and totally unfair to novice marine aquarists. Let me explain:
Keeping "easy" inverts, such as some species of soft corals, cleaner shrimps, Featherduster worms, etc. are actually easier than keeping fish. They cause much less pollution, and therefore place less of a bio load on the system, which maker filtration a lot less critical. They don't get diseases such as "Ich", and many do not need much feeding either. You do need a minimum amount of light in order to keep corals and other photosynthetic animals. Fortunately the easier "low light" softies, such as brown or green Star Polyps (Pachyclavularia and Briareum spp.), Mushroom corals (Sarcophyton sp.) and Devils Hand or Finger Leather corals can be kept under normal fluorescent lights - though you would need quite a few tubes....
The "difficult" part of keeping a reef tank is when you also want lots of fish in it. This just does not work very well, and is not to be recommended to newbies. Rather start off with a "marginal reef" tank, with lots of live rock, a deep live sand bed substrate (both very important elements of your filtration, as well as being interesting in their own right), some "easy" soft corals, some tube worms, etc. and only a few reef compatible fish.
Do your research first, though. Learn as much as you can about the different filtration methods, compatibility of livestock, food and feeding, and everything else you can pick up... Then, carefully plan your set-up, and GO SLOWLY. In this hobby there is a saying:
IN A REEF AQUARIUM, ONLY BAD THINGS HAPPEN QUICKLY.
If you stock your aquarium before it has cycled properly, you will probably kill your animals. If you stock to rapidly, your tank will have another ammonia/nitrite spike, again probably killing your animals. At best, you will have problem algae, and sick fish. Remember that this is a long-term hobby. It is not uncommon for a tank to only stabilise properly after 6 months. Your corals can outlive you, and even the most common fish can live longer than 20 years, if you do your bit....
Equipment does not *have* to be very expensive, but it *usually* ends up costing a great deal more than you originally had in mind.
Although one could successfully keep very small marine tanks, this is a specialised field, and is not the ideal for a beginner.
The disadvantages of a larger tank are mostly financial:
This will depend on the type of set-up:
The light "Colour temperature" is also very important. Water "absorbs" the longer wavelength light (the red, orange and yellow colour) at a shallower depth than the shorter wavelength light (green, blue and violet). If one descended from the surface of the ocean, the red light would disappear first, and the last light remaining at depth would be violet.
Sunlight at the water’s surface has a colour temperature of 6 500K. I don't have exact figures, but I believe that the 10 000K light spectrum approximate a depth of around 10m (33') below the surface, and the "bluer" 20 000K spectrum is equivalent of light at a depth of about 20m (66')
Because *most* corals live closer to the surface, 10 000K light would actually be more natural for them than 20 000K light. If one were to set up a "deep water" tank, containing species living at greater depth than that of a "normal" shallow reef, one would be better off to use the 20 000K lamps.
The following links may explain this in more detail:
Reef Tank Lighting
Photosynthesis/Irradiance (P/I) Curves and Why They Are Important to ReefKeepers
To be honest, whenever I hear this term, I envisage this large, all glass tank, riding around on a bicycle …..
The term "cycling" is actually a bit of a misnomer, IMHO. In our hobby, it usually refers to a state where the aerobic component of the filtration system has "matured" to such an extent that there are enough aerobic bacteria present in the system to convert the ammonia/um generated by the tank's bio-load into nitrite, and the further conversion of the nitrite into nitrate. In actual fact, this only completes of the first phase of the actual nitrogen cycle.
Until a few years ago, that was as far as the process could go, resulting in a slowly increasing level of nitrate, which could only be reduced by partial water changes. Thanks to the "discovery" of live rock, and later of live sand, the "'cycle" can now be completed by anoxic bacteria living in these substances, further converting the nitrate into inert nitrogen gas.
In hobbyist’s terms, a new system is considered to be "cycling" when there are still detectable levels of ammonia/um and/or nitrite in the water. A system is considered to have "cycled" when these levels drop to zero, and the nitrate level starts to increase.
The important thing to remember is that a tank does not "cycle" only once. The system will reach equilibrium, where there is enough aerobic bacteria living in the filters to maintain an undetectable level of ammonia and nitrite with a given bio-load. Any increase in the bio-load, such as when a new fish is added to the tank, will upset this equilibrium, by "flooding" the system with more ammonia/um than the bacteria can digest. Obviously, with more "food" available for these bacteria, they will multiply (assuming that food was the limiting factor), and in time the system will reach a new equilibrium, able to handle this increased bio-load. This does take time, though, and in the meantime the increased level of ammonia and/or nitrite could be poisoning all the fish.
How to "Cycle" a new tank.
In order to "cycle" a new set-up, one must introduce a source of ammonia/um. In the past, this was usually done by adding some hardy fish (usually Damsels) to the new tank. Although this works very well in a bare tank (with outside filtration), it’s not recommended for two reasons:
I would start the cycling by initially only adding the sand. Let it settle for 2-3 days, with all the circulation going. Then, add one or two pieces of base quality live rock, and one or two dead prawns or cocktail shrimps (the food type, not a dead one from a LFS - that could be carrying any number of diseases!). At this time, start testing the water for ammonia daily. You should notice an increase in the reading, and after a few days, the reading should stabilise, and then slowly start to drop (this could take 1-2 weeks). At that stage, start testing for nitrite as well, and keep on testing for ammonia. You should now notice an increase in nitrites, and a decrease of ammonia. After another week or so, the ammonia level should be fairly low, and the nitrite level should have reached it's peak.
Once the nitrite level has also started to drop, you can add the rest of the base quality live rock, and once both the ammonia and nitrite levels have become unreadable low, you can then add the good quality live rock (containing many interesting inverts). This could cause another ammonia & nitrite "spike", although it will be much smaller than the first. This is not critical if you’re patient - just let the tank settle for another month or two before adding fish. This should give the macro algae and small critters on the LR time to recover, and to multiply to sustainable levels in the LR, and to migrate into the sand. During this time, you should also add some live sand, and/or some live sand "starter kits" and "reef janitors". Also, don't be concerned with the initial algae growths - it's quite normal to have some diatom, cyano, and hair algae growing as the maturation progresses.
"Cycling" a new system with uncured live rock.
Introduce the LR after the tank's been up about a week, and use it to cycle the tank. Wait at least two months before introducing the first fish.
Deep Live Sand Bed filtration:
A general rule of thumb is to have a 4" layer of fine, graded sand, although the actual thickness would depend on the size of the sand. The finer the sand, the less water flow is possible between the particles, and the thinner the layer needed to achieve an anoxic zone in the sand. IMHO the very small size sand, though "perfect" for nitrate reduction, is not what occurs naturally, and does not allow hiding places for many small critters. My sandbed is made up of ~75% natural sea sand (shell grit and silicon sand, ranging from ~0.5mm to ~ 6mm in size)) and ~25% crushed coral sand (approximately 1-2mm in diameter). I have found that the areas containing the coarser particles have a greater abundance of small critters.
Here are some links to interesting articles (hope they still work...):
The Whys and Hows of Sand Beds
The Quantitative Comparison of Two Nutrient Removal Systems
It's quite human to want to add all kinds of things to help our creatures. The manufacturers and shops know this, and make a lot of money out of this "weakness". Unfortunately, many of these "snake oils" are just expensive water (perhaps coloured). Others do add trace elements, but an excess of many of these elements are actually detrimental to your tank (amongst other things, it tends to make cyano and hair algae grow...).
Under normal circumstances, one should only add buffer (to keep the alkalinity up), and a calcium supplement if/when there are hard corals (LPS or SPS) or other calcium using life forms in the tank. Either use one of the "balanced" two-bottle supplements, or add Kalkwasser. If you do not have many calcium absorbing animals (such as corals), then you probably don't need to add calcium supplements. You then also don't need those high calcium levels normally quoted for a reef tank.
Note that the long-term addition of calcium chloride will result in a gradual increase of the chloride content of the water. This will eventually result in your water's chemistry being quite different from that of natural seawater, which is not good at all
Apart from this, I would not add any supplements unless I could test for it, and found a deficiency, as regular partial water changes would replenish the trace elements used up by the inhabitants.
I realise that I've only skimmed the surface of starting with this great hobby (pun intended), but I hope that this article can be of some use to someone out there…