Hmm...I DO have a large bioload in my tank. How many fish should one keep in a 33 gallon in order to provide a low nutrient tank in order to keep corals?

It's hard to say what is an appropriate number as there are too many variables to that question. The real question is; can your filtration handle the bioload your livestock is producing?
If it's a bioload issue you will likely see algae blooms IMO. However if you are measuring amonia there is a problem and tank has either started to cycle or something died. What are you using for a skimmer? Is it running efficiently? Also what is your water temp? This can drasticly affect sps.