If a tank has low hardness, it is not going to have
much buffering capacity.
Not exact matches
(Fully
buffered, with heat
capacity - > infinity, T ~ (average insolation) ** 1/4; unbuffered, for a simple model in which the sun switches full on for 12 hours then off for the other 12 hours, T ~ 0 at night and ~ (2 * average insolation) ** 1/4 during day, so Tav ~ (0 +2 ** 1/4) / 2 = 0.59,
much lower than the
buffered case).
On the Moon, the effective
buffering depth is ~ 1m, which for comparison gives about a tenth of the
buffering capacity of the Earth's atmosphere, while the sol is of course ~ 29 times as long, so the temperature swing of the lunar surface is
much greater, reaching ~ 120C during the lunar day.
Which is why continental climates have
much colder nights than maritime climates (heat
capacity of water versus soil, plus land - sea convection which allows the atmosphere to continue
buffering during the night).
If reverse weathering is taken into account, then the
buffering capacity of the CO2 system extends for
much longer periods.