Sorry to hear about the red bugs but never fear, I just anihilated my red bugs about 3 months ago and every thing is fine. Please look at the link below. I used to this site to research proper tank treatment and dosage. You will more than likely only need 1 pill. Remember to remove any inverts from your system because interceptor kills them. Good luck!!!
Supposedly a single treatments should work. As they don't have eggs. I did a single treatment a while back and have not seen redbugs since. For 80 gallons a single dose would only use 1/4 to a 1/3 of a large tab.