do sterazin medication kill beneficial bacteria

[ganesan]

Recently some discus in my 90 gallon tank started to rub itself against air tubes.I suspected that they were flukes or some parazite infection and added just 65 drops of STERAZIN medication from waterlife product into the tank directly (small dose as the literature says 1 drop/litre) and kept my 6 large bio sponge filters running,also my canister running.I turned off the UV.On the the 3rd day I changed the water by 50% and I have seen marked improvement with the discus.Their fins are upright and appetite great.I did not medicate again.I was just wondering whether the medication STERAZIN would have killed beneficial bacteria,although the catalogue says that STERAZIN is safe to use with biological filtration.I used less dose as the tank (just in case it does not kill the beneficial bacteria) holds about 380 litres and i ought to have added so much more medication.Actually it says to use on the 1,3,6,8,10 days with partial water changes.
Today on the 4th day I added 4 capsules of microbac capsules from ocean free products for building up beneficial bacteria should some have died into the tank.Fish are doing fine.My question is can I live the tank running as it is and keep changing water 20% daily as I normally do.