Shorty I seriously considered getting a strand of water primrose out of my sediment pond and put it in. It would likely have snails or eggs on it.
Since I had the fish kill in it from the chicken litter runoff, the primrose has turned a dark green/reddish healthy look to it like I have never seen it in other ponds. It really likes those nutrients. And snails galore. The RES I restocked should be well fed for a while. I think if I took some primrose from this pond and put it in the new one, the biological process would definitely start.
I actually did put snails and algae from my main pond into my forage pond which has RES only when it was new.
A person has to be a die hard RES fan to stock snails.