Help! Can you smell the difference between Giardia and Tritrichomonas foetus??

Hello Cat Site friends. I have been lurking and reading over the last few months as I've battled ringworm and now am onto another invisible demon plaguing my kitties and causing stinky loose stools/diarrhea

Their fecal (Ova and Parasite with Ceintrifugation) returned positive for Giardia after which my vet put them on a 7 day course of Panacur (fenbendazole). I didn't notice any changes to their stool consistency during the treatment week nor in the week following. My vet mentioned that she's been seeing stubborn strains of Giardia this season and suggested a 14 day course of metronidazole. We just finished day 7 and the stinky odor has not diminished at all and their stools are still very loose. 

I have read "all the threads" suggesting that Giardia is often misdiagnosed when instead the kitties could be suffering from Tritrichomonoas Foetus. I am terrified that this is what we might be seeing in my cats. My questions are:

Can you smell the difference between Giardia and Tritrichomonas? (sorry if this causes too graphic content)

At what point during their treatment (if we actually are treating Giardia) should I expect their stools to stop smelling so horrid and turn solid?

Any other supportive tips or recommendations for feeding and caring for them?

I suspect in 2 (of my 4) kitties a concurrent food allergy as they have been scratching their faces quite a bit. I have only had them since the very end of May. 2 are from one litter (suspected allergy). They other 2 are a momma and her kitten.

Thank you in advance for any help you can offer!

No, but you could have your vet run a fecal PCR test. You may want to take a read over this information about using digestive enzymes and consider trying it after consulting with your vet. I would also suggest giving them a probiotic that contains S. boulardii as well which will help restore their digestive flora and heal their gut after both the infection and antibiotics.  Nexabiotics is a good one.

Here's a link with info about probiotics and  dosage. 

http://www.littlebigcat.com/health/giardia-natural-treatment-protocol/

http://www.rawfeedingforibdcats.org/probiotics-for-cats---why-and-which-ones.html

Thank you for the reply missmimz! I will ask my vet to run a PCR to confirm what organism we are dealing with. They have been on a probiotic (MitoMax) which contains s.boulardii but I have no idea if it's helping