The ocean’s chemistry is really pretty simple: it eats rocks. It supports organisms that, from microcellular up, eat the dissolved rock and eat light of a favored spectrum, which energizes their little cell-parts and makes the eating re-constitute into shells, tissue, skeleton. If conditions go ‘off’ it fosters areas of the food chain that ordinarily are very sparse, and other things start to grow—like cyanobacteria, which lives on sunlight as a sheet of red thick feathery slime, photosynthesizes simple sugars, and gives off oxygen bubbles.
If it weren’t for cyano, earth wouldn’t have an oxygen atmosphere, wouldn’t have recovered after the Permian Extinction, and wouldn’t have green plants—which developed incorporating an element of cyano. It’s part of earth’s balance: the atmosphere goes wonky enough to distort the solar spectrum and you get lots and lots of cyano. Piles of it.
If it happens in your tank, alas, not so good. So you have to keep your lights burning true to the sun’s spectrum…and metal halide bulbs don’t so much burn out as ‘burn down’, or yellower.
Things die, and the ocean dissolves their skeletons and new critters suck it up and build their skeletons. The precise amount of calcium ocean water can dissolve is 2 tsp a gallon, unless the ph is high. Then maybe 2.5. People put white vinegar in their tanks to force a bit more into solution, but you have to supply the calcium in the first place…and what we use is, yes, Mrs. Wages’ Pickling Lime, meant for cucumber pickles. Works like a charm, dumped into the fresh water we add as make-up for evaporation.
A marine tank is surprisingly little care, so long as you keep fresh water slipping in via a float switch (a lot like your toilet tank) and keep the water circulating and a high rate of speed and the calcium in the water sufficient—since no more than 2 tsp WILL dissolve, I don’t even measure: I dump a whole packet in and trust basic chemistry to happen. You have to change out the lights periodically. And there’s a device called a skimmer, which produces bubbles in a chamber and extrudes froth, which is amino acids the system doesn’t want: with that, pure water, a good salt mix you buy—things are remarkably stable and coral grows and fish thrive.
A lot of people get spooked off aquaria at the goldfish level—and the pure answer is—goldfish are a type of fish better off in ponds, not gallon jars. They don’t get enough exercise and eat too much: recipe for bad health; and one gallon doesn’t provide enough oxygen, either: if in the least dirty, the water carries even less oxygen. And tapwater is full of stuff they shouldn’t be breathing, even if you correctly use water conditioner to remove the chloramine. Small wonder goldfish demise. They’re NOT an easy fish in the first place.
The hobby as a whole has marvelous equipment compared to what we used to use. We’ve got one freshwater and one marine tank, the latter of which shouldn’t have been as much trouble as it’s been, except that I got some iffy rock, which has taken months to condition into honest live rock—[meaning it's got bacteria living all the way through it and it's soaked out all the phosphate it came in with]—which now serves as a very important biological filter. It’ll be great rock, now. And the coral should start to grow.
This is how the tank arrived. 800 lbs. In the street. If it hadn’t been for Mike and Patty Briggs, who drove up from the Tricities (150 miles one way) to help us, and Tim Martin who came straight from work—we’d have been in real trouble. If you’re interested, I’ll show more pix of the tank during setup.