I cannot determine what the weed is from the picture, however, it certainly falls into the category of "broadleaf aquatic weed" and most all of these weeds are best controlled with copper products like copper sulfate or Cutrine Plus.  Both of these are safe for use in ponds used for drinking water.  You may find those products at a local fertilizer/chemical dealer, hardware or box store.  Aquashade will only color/shade your water and help prevent aquatic plant growth, however, it alone will rarely contain pond weeds.  I hope this helps!