A controller is never ‘required’ - they just make things much easier by automating, monitoring and letting us check on things while we are away.
How much of a perterbation each tank can handle before issues arise really depends on the individual setup, but things happen with every tank, and the sooner you catch them the better.
How much of a perterbation each tank can handle before issues arise really depends on the individual setup, but things happen with every tank, and the sooner you catch them the better.