silly question, but does your tank matter?

[itf]

The reason is, aluminum is a great heat dissipator - heat goes through it slightly slower than through air, so to speak (reason why, cooking folios are made of aluminum, heat goes through them easily); steel isn't as much. Heat two cups or saucers, one made of aluminum one made of steel, let them sit for one minute and the aluminum would be near cold, while you wouldn't want to touch the steel 😀 hope this helps solve some doubts 🙄

Yes, I agree, the thermal conductivity of aluminium is greater than steel, but that of steel is greater than plastic. After re-reading what Roger said, I realised that is what he was saying and so a steel tank in a water bath gives a more constant temperature than plastic. Where are the aluminium tanks?

I usually use Rodinal 1:100. For example, one roll of 35mm film in each tank, the larger tank one has 5ml of developer diluted in 500ml water and the smaller tank has 3.5ml of developer in 350ml water.

So a roll in the large tank gets the same dilution, but more of it. This would make a difference to the results.