humble furnace
supplementaries fire pits can now accept lingering potions with a simple right click, accepting a potion, will make the block emit some sparks that match the colors of the potion (visual cue that something weird is happening with this fire pit!), after accepting the potion, the fire pit will now emit a potion effect aura of 5*5 blocks, effectively creating a mini beacon with a limited range area of effect and with any potion effect in the game. (even bad ones like wither or poison) 
humble furnace
I was thinking of it being permanent because of the limited range of action and it would give the player a good reason to create lingering potions and firepits. I imagine a situation where the player is running from zombies with half of their life until they arrive at their camp with a firepit with regeneration. Essentially functioning like a safe space (like how the campfire works in some videogames).
But for balancing purposes i think maybe it should be limited but if it's the case i think increasing the range of effect would be nice to not make it so niche
humble furnace
Like in duration
The main idea is permanent area of effect until the fire gets put out 
rocky dagger
Does seem quite op
humble furnace
Does seem quite op
true, but then it would only by like a normal lingering potion if it's not the case
or that's my analysis
rocky dagger
would even make lingering potions less useful too