Sam, do you have the pots up off the ground. I have found ants to be in the bottom of my pots and most of these pots where on the ground. I made life miserable for them so they would leave and put pots on lifts/feet. With most of my seedlings and other Adeniums, they are all up off floor or ground.
I would not soak them. Don't risk losing them.
Rick

Hi Rick.
Yes, the pots have always been up off the ground. My husband built me a bench off the fence just for my seedlings. I've just recently found an old security screen to put them on for added air flow.

I think I'm going to have to re pot them and get rid of the old dirt.... I didn't want to re pot them so soon :-(

Hopefully having them up on the mesh will help stop them coming back.

Sam