Aquarium science: biology, chemistry and physics

Biology

Bacteria, plants, animals, and what eats what

Nitrification as the last twenty years of microbiology actually describe it, not the two-genus story in the aquarium books. Where the animals in a jar of pond mud come from, which is the sediment and not the water. Why a plant fed at the root stops feeding at the leaf instead of doing both. Leaf litter as the fuel that runs the whole thing, and tannins as the brake on it.

It also states plainly that the hobby rule of a minimum of six fish has no source behind it, because we went looking and there is not one.

Chemistry

The equilibria, written out, with the working shown

The carbonate system in full, from the four equilibria down to the single line that says a limestone rock cannot make your water harder than a fixed ceiling, and that the ceiling moves as the cube root of carbon dioxide. The ammonia equilibrium, which is the most useful chemistry a fishkeeper can own, because how much of your ammonia is the dangerous kind depends on pH and temperature and on nothing else. What a water conditioner is, as a balanced reaction. And the unit conversions, because the hobby quotes hardness in at least four incompatible ways.

Physics

Gas across one surface, light through two, and heat you cannot switch off

Oxygen enters a tank through the top and nowhere else, and when you write that down the volume cancels: only depth matters. That single result explains why a shallow tank needs no air pump and a deep one does. Then altitude, because every oxygen table in the hobby is wrong in Yerevan and wrong by a knowable amount. Then optics, including the honest answer about dispersion. Then flow, heat, and the floor-loading calculation we got wrong and had to correct.

Archive

Three hundred and fifty six papers on one lake

A century of limnology on Lake Sevan, open access, in Russian, and indexed by nobody: not Scopus, not Web of Science, not the Directory of Open Access Journals. We collected it so it can be searched in one place. Every record links to its PDF.

How these pages relate to the rest

Nothing here is new. It is the same evidence, sorted by mechanism.

If you want to do something, the practical pages are better: materials and water, cycling, planning a tank, water changes. If you want to know why the practical page says what it says, start here. Each of these four links back to the page that covers its topic in depth.

Two smaller pages are science projects rather than reference: a jar of pond mud on a windowsill, which is the cheapest ecology experiment there is, and Lake Sevan, which is the one place in the country you can go and look at the whole system at once.