Yes - didn't I say that? I thought I mentioned a spiral like the one "Biggles" made so nicely by welding plastic. Actually, however, the two swirl filters I have in the garden right now (photos are somewhere here also), work with excellent effectiveness - they only have two spigots inside and aimed to strike the sides of the tube at a downward angle. Gravity and water surface tension do the rest. Also, I've run the siphon in the photos in my fish tank already, learned that it filters solids very well without the cone or spiral - same principle of physics the reason. Adding the angled surface is another experiment - I'll let you know what happens (don't I wish I could weld like "Biggles?").
Thanks for you interest and remarks.