Too early for milfoil?
 

I just noticed some slimey green stuff with tall spires growing on rocks in the water. Could this be milfoil, or is it too early for that? It's not real feathery yet, but it is the same shape. If it is milfoil, we will gladly attack it by hand, but is there also any product we can safely use to eradicate it?
As always, thanks for your help!