My Husband uses the Neti Pot.
He has sinus issues. It helps him.
My daughter, from 5 years old, uses the Neti Pot too, IF she is sick.
You are using the nasal wash, TWICE a day, in your daughter.
I would say... once a day is enough.
BUT she has Asthma.
I have Asthma.
I do not use the nasal washes.
I don't need to.
You are using the nasal wash on your daughter... for her SINUSES, right? Because, this is not an Asthma... solution.
You need to be sure... to do the nasal wash.. properly... OTHERWISE... the Sinuses will not drain properly nor, dry out... properly. If you do not 'blow' out and let the water drain out from your nose, properly.... then, you will always have moisture in there... and it will create... an infection... or make the Sinuses... worse.
THIS is what may be happening to your daughter.... since you said she is Congested... and has "horrid breath".... from the drainage into her throat....
To me, THIS is the problem.
In her Sinuses.
It is not the frequency of how many times you use the nasal wash on her... but IF you are doing it properly... AND having the water in her nasal cavity... drain properly.... and completely.... and that it is drying in there. Not having residual moisture in her sinuses.
For us, we do not use powders in our Neti Pot. Just warm water. OR, the special "salt" that comes with it.
all the best,
Susan