This is a cistern, very interesting, one can walk around it, there is a raised walkway,
see more here clearly a cylinder is round, as to tank, likely covers all.
Words imported into the English language do intrigue me. A "Plumber" is a worker of lead, about the only Plumber today tunes organs, it seems lead replacements alter the tone.
Every trade has them, electrical trade it is the "Lamp" "Bulb" and "Tube" although clearly the lamp refers to the whole unit, and it could have a mantel, wick or bulb inside, we see so-called electricians trying to tell people what the items are called, and the regulations don't help with references to "Lighting fittings using filament lamps" going back to the 13th edition.
Bulb refers to the shape, as does cylinder with pipe fitting trade. But most of the words we use, have a wider use, transformer
is a good example, in the electrical trade we think of a wire wound device, but these have been replaced with electronic devices which not old transform the voltage but also the frequency, and it leaves us with a problem, as the electronic version often will not work with LED lights.
So however much we think it is the wrong name, we have forced to use the name given to it by manufacturers and suppliers
as otherwise we get the wrong thing. I remember wanting a head lamp bulb, so ordered a head lamp, and got all but the bulb. The buzz word today seems to be combi
and Hybrid. And they can mean such a different thing, Hybrid with 2 wheels means on and off-road, with 4 wheels it has electric and liquid fuels. Samuel Johnson must be turning in his grave!
I think this tank has a hole in it
? But I am a bit of a butcher, I would bend the float bar so less water in the tank, until "Plumber" arrives to do a proper fix.