I always have to ask.... are you sure it's planaria and not rhabdocoela flatworms? Many people often think rhabdo's are planaria when they aren't.
As far as spirulina goes, you can always get tabs or 'pellets' instead.
When I tried the diet advice given to me, I was feeding Ken's Fish Veggie Sticks (there's two versions) and then either flake food (not sure of protein source but they're red flakes!) or another protein food I can't recall what it was. I was also given some other veggie/algae food, although unfortunately the place the food came from is gone... so not sure exactly what foods they are anymore.