Hi Maryann,
Marine Ich is a disease that is linked to water quality. Fish will get stressed, their imune system goes down and they get sick. Marine ich is a sign that something is wrong with the water. Sometimes ich is introduced when a new fish is placed in the tank without the quarantine required.
You tank is still cycling ( as per your other thread ).
If you have not been doing the required water changes ( as per replies in the other tread ), then
ammonia etc will be in the water, and this will be affecting the treatment.
It is important to have good water and reduce the stress to the fish being treated.