Just FYI, bottled ammonia is available at virtually every grocery and department store in the US in the cleaning aisle. It's super cheap and you can cycle about 100 tanks with a single bottle of the stuff.
Are your tests good?
The only other thought I've got about this is that your plants/algae might be monkeying with the ammonia levels in the tank. They see it as food and will happily slurp it all up. I normally don't bother cycling a tank if I've got a reasonable amount of live plants in it and instead just add stock slowly. The plants keep things clean for the shrimp/fish and all is well. By the time it has sat long enough for the filter to actually be needed the tank has cycled. Your mileage may vary, of course.
Are your tests good?
The only other thought I've got about this is that your plants/algae might be monkeying with the ammonia levels in the tank. They see it as food and will happily slurp it all up. I normally don't bother cycling a tank if I've got a reasonable amount of live plants in it and instead just add stock slowly. The plants keep things clean for the shrimp/fish and all is well. By the time it has sat long enough for the filter to actually be needed the tank has cycled. Your mileage may vary, of course.