stupid chiller question

[Willow]

it seems that the source of my leak (guess) is coming from where the black compression nuts attach to the pvc tank. if you look down under the long copper pipe you can see a lot of white residue. it feels like the black nuts have a little play in them. im kinda scared to pull them out because i don’t know what’s behind them and if i'll be able to get them back in. if i coated the joint with silicone and tightened up the nut do you think that would work?