Natural method
The 'natural balance' method seeks to imitate the ocean shore or shallow creek as far as possible by using local materials. If you are within a car drive of the sea or an estuary, then why not try your luck? Basically the sand from the shore will be kept to minimum depth, even to zero in the feeding areas.

Collection
Collection seems best from the leeward of a reef, or at the time of the receding tide when freshly trapped water and live specimens are found in prime condition. Walking along the receding tide line with your back to the sun helps you to detect the telltale ripple and the glint. Before transporting home any bivalves (cockles or mussels in England, others elsewhere) or anemones it is essential to put them in a small jar of sea water to eject all the filth from their gut. One bivalve dying in the evening can cause a clouded smelly tank by the morning. During transport back please don't overcrowd; your specimens will pay for this mistake with their lives. You may need several containers; incidentally, what is their color? In natural life how often do fish meet a bright red plastic bucket? They get unnerved trapped in an all surrounding single colored glare; and fright or shock can both kill - now or later. Darkness helps, so put a lid on it.

Why neglect to collect the humbler shrimps and crabs etc, as scavengers, or sea weedy, algae-covered rocks, not to mention anemones which can be prised from underneath with a knife. Maintaining a proportion is essential, giving 'natural enemies' distance to keep away from each other; remembering the needs of the free-swimming and the crawling.

All containers must be free of metals and non-toxic; all dying. dead or decomposing things will be removed urgently - preferably before it happens! - and freshly gathered water will be a fine stand-by. The harm one single dead crustacean can do, before you realize that death has occurred, will surprise you; the same goes for the algae-covered rock - greatly appreciated by the fish while alive, but lethal when decomposing. So do use them, but you should ever be on the watch.

Setup
Given these rather dictatorial do's and don'ts the scope is yours; at the moment no one knows enough to breed marines on a large scale to meet commercial timetables, so there are no true experts, only enthusiasts like yourself. So why not experiment? The next step in progress may easily come from you.

Materials and conditions being local you may not need artificial lights or artificial heating, aeration, etc. Some 'natural method' people scorn such things - yet the ocean is bigger than your tank, and the constant eddies and surges are huge scale and are never never ending. Aeration could help. It could also do so during the transport back to the tank and battery-operated air pumps are widely available.

Probably the most important single tip is to put enough light, day and night, on your tank to enable green algae to be established first, all along the sides of your tank. Then start introducing other things. Inside the tank, hiding places and territorial markers are essential. The same applies to caves, dark and protective. If you clean out your tank then these must all be restored exactly; imagine how you would feel if they suddenly moved your kitchen on the roof and your bed into the garden. It's not decor, but survival.

Yet you must be able to examine and peer enough to spot and remove the dying, not just the dead; including the foods, the droppings, and the refuse 'balls' ejected by the anemones for instance. Anything that can hide the droppings is hindrance, even an internal filter that collects mulm underneath its curved flanks, and decor has to be strictly functional (for shelter and for pH stability).

Any grey or black spots are highly suspect; grey clouds in the water almost always denote decomposition underneath.

When in doubt, smell it; if it does not actually smell fresh, then assume it's bad.

Dead, grey, black spots on coral can be bleached (using household detergent-free bleach), or just knocked off with a hammer and chisel.

Excess surface scum may be the ejected body mucus of the Lion Fish, for instance, and needs to be skimmed off - frequently.

Shells
The coral, the rock, the sea fan, and the red pipe organ coral all can look nice. So too can the shell, if you're sure it's clean and hard. Prudent aquarists refuse point blank to accept any shell as clean unless obviously occupied by its original living owner; hermit crabs that borrow an empty shell are still suspect. The trouble is that dead fragments, shriveled and dehydrated even for years, come to life in water and start decomposing. You need to soak shells in strong detergent, free from bleach, one to three cupfuls per gallon, turning the shell round and round til all air bubbles have been eliminated particularly from the twisted, inaccessible parts where air might get trapped. After two or three more days, thoroughly rinse, before use. Even then the prudent aquarist makes periodic checks to see that nothing has drifted in and got trapped.

Artificial shells and china ornaments serve well. Naturally everything is better washed in salt water especially sand whose beneficial micro-organisms could be killed by fresh water. Many people use the sea water again and again, allowing it to settle clear in a dark storage place, and carefully siphoning off the top. Please note that the micro-organisms can be killed almost as easily if suddenly washed or flooded by salt water of a different specific gravity; this can be important.

Many an aquarist has such 'natural method' marine tanks that have gone on fine, and many a yarn is (quite truthfully!) told of 'loved for years and never changed the water.'

Other layouts
If your area is not near the sea, you can still follow the 'natural method' in the sense of keeping simple things in a simple way. A beginner should never be too venturesome; starting small and graduating up, seems to be the best policy.

You'll need artificial salt, and aeration; filters and ozonizers according to taste (and pocket!).

Some people paint the base of the tank with a non-toxic marine aquarium sealer, sprinkle it with 1\8 of an inch of sand, leave to dry, and that's that. Others use an undergravel filter lined with filter wool and then covered by 1\2" of marine sand or of crushed coral. Yet others leave most of the base bare, pile the sand or coral round an inverted plastic household funnel fitted with an air line.

All three 'work', but arguments rage. For example, many feel that the undergravel filter should fit snugly over the whole area, and have such a good 'grip' at the outer limits that water cannot seep in, except through it; others use probing and radiating under-sand tubes that leave relatively large areas free.

All aim to keep down the hostile bacteria caused by decomposition or by dirt, and to encourage the growth of helpful nitrates, partly by the flow of filtered water, partly by 'correct' pH of around 8.3 (helped by the presence of crushed coral), and partly by use of the multi-purpose and multi-layered filters. There seems to be growing agreement that more than three layers to a filter is helpful. Increasingly clear is one important fact; you should spend most of your budget on buying equipment (not fish!), the second and the third filters are used simultaneously are far far more advisable than a second or third fish. The time will come, later, when you can add these; the filters come first. This really is important.

Hints to remember
Many lay great stress on allowing the helpful micro-organisms to get a grip first; a process that can take two or 12 weeks, and which automatically reduces the level of the hostile nitrates, and stabilizes the pH.

Many insist that algae be grown first, either in the tank itself, or preferably in a separate external filter which is equipped with its own lighting that can stay on constantly; certainly the fish health and appetites are improved with water that has come from algae-saturated waters. Of course, the algae must be maintained and not allowed to start decomposing!

Patience is essential, even a pH reading cannot be taken, after a change, for some 24 hours; the same applies to specific gravity alterations and readings.

The standard rule is to soak everything in salt, first, before use including the filters and their carbon, etc. If you are wiping anything then dip your clean cloth in salt water first, or at least have damp salt on it.

Sudden changes don't help at all. To go from a specific gravity of 1.025 to 1.000 abruptly, eg. even for washing something, can be lethal to beneficial nitrates. Sudden shock like putting on the tank lights can harm, so always put the room lights on first. Metals must be entirely absent - not in the rocks, lamp clips, wires, etc - plastic coatings being essential.

To get the biggest surface feasible on your aquarium has always been wise advice; with marines the rate of filtration is perhaps even more important - you may need real heavy waves of movement, as in natural life, surging and eddying with evident force.

Temperatures are similar to those for their freshwater cousins, around 75 degrees F with room to fluctuate 8 degrees F either way. Some fish like the low ranges, some the high; so many factors are involved such as seasons, age of fish, their health, etc. When in doubt, do as you might for freshwater tropical fish.

Urine decomposition is aggravated because the lowered oxygen content of the sea water induces a faster intake rate by the fish, with consequent increased urine. If the fish start to breathe faster then you'd better start checking; a part change of water would probably help.

There is no virtue in putting the air pump where it sucks in tobacco or kitchen smells; better to place it outdoors on the window ledge and to run in an extra length of plastic air line on the theory that cold is better withstood than tobacco smoke - something an ocean fish has never met before.