I also use the Eheim with no problems (I've never seen the Apex in action, so comments here are useful to me). I feed a mix of pellet and flake, with a bit of powder all churned together. The pellets sink next to a Tunze stream and are pushed into the tank, but the flake and powder floats ...
Instead of a feeding ring, I added an Eheim surface skimmer
Next to where the food drops in. Pellets still sink and the Stream takes care of them. I've removed the sponge/filter from the skimmer, so this takes the flake and powder and carries them underwater, spitting them into the current. Works extremely well, has done for years.