Air Conditioner Evaporator coil cleaning, due to debris in the drain line that caused pan underneath unit to fill out with water. Coil was relatively clean but rust pieces were in the evaporator's plastic pan and probably they clogged the pipe.
Clean dirty coil with one of these foams:
Home Depot: http://www.homedepot.com/p/AC-Safe-Air-Conditioner-Coil-Foaming-Cleaner-AC-920/100599017
If you want to use tabs as proactive action here are the links for them.
Home Depot: http://www.homedepot.com/p/AC-Safe-Air-Conditioner-Pan-Tablets-6-Pack-AC-912/100665383
UV LIGHT: https://www.amazon.com/Honeywell-RUVLAMP1-Air-Treatment-System/dp/B000F0DWWI/ref=sr_1_11?ie=UTF8&qid=1503409747&sr=8-11&keywords=ac+uv+light