What is the theory behind soaking soil? I don't think there is any mention of it in Walstad's book, although I could be mistaken. She does say that it takes 6 weeks for the soil to 'activate' - is this something to do with why you want to soak it?
I have recently set up an EN tank and I put the soil straight in (John Innes No.2), and three weeks on the plants are already growing (some of them well enough to make me look across to the other tank's CO2 injector with bemusement), and there is just a tiny bit of hair algae, so I think it is ready to go, from the word go as it were...
What do you think?