for
ICH you should raise the temperature slowly to 84 degrees (one degree per hour) for two weeks. most people prefer this method because it doesnt add medications, which can do more harm than good and also kill your cycle. you'll want to add an airstone as well because the higher temp will lead to less oxygen in the water
however, IMO a bigger problem is two oscars in a 40 gallon tank.....oscars get up to and over 12 inches and one will probably end up killing the other in a 40 gallon and the growth on both of them will be stunted. a 55 is the absolute minimum for ONE oscar, for two you'll need 125+ gallons. if you dont intend to upgrade your tank, i have to suggest that you either return them to your pet store or sell them. i understand that they are probably only 2.5-4 inches right now, but they will not stay that size.
when you say normal, what do you mean specifically for the readings? if you just got your tank set up then it probably is not cycled, and you should either do daily 50% water changes with prime or return your fish and go for a fishless cycle, much less hassle, much more peace of mind.
http://www.fishlore.com/NitrogenCycle.htm http://www.fishlore.com/Articles/TheNitrogenCycle.htm
this is the site i use for almost all of my oscar info
http://www.oscarfishlover.com/index....ank-setup.html