Decanter of Endless Water vs. Persistent Fire or Acid Damage

If a party member is suffering from persistent fire or acid damage, and I aim my decanter, set on "fountain", at my buddy, would that count as an "Aid", reducing the flat check?
And, if we're in encounter mode, would I need to make a successful attack to effectively 'soak' the affected area?

I would count it as 'particularly appropriate help' for an assisted recovery check. Your ally will presumably not be trying to avoid the water so I wouldn't require an attack roll, especially since you'd have to be ajacent to them due to fountain being only a 5' long stream

I would also run that as Assisted Recovery. I would not have the activation of the item be additional action cost though - just the two actions for assisted recovery and having the Decanter available with a hand free to use it.

No roll is needed. But you do need to be adjacent to the ally you are helping.

The benefit is that Aid only gives a +1 or maybe higher if you are at higher level and proficiency. Assisted Recovery gives basically a +5 bonus (by lowering the DC instead) and gives a flat check chance immediately - meaning before they take damage again.