new to diesels 2002 F250 Water in Fuel
 

I have a 2002 F250 Superduty with a 7.3 198,000 miles. Last night while driving around the water in fuel light came on along with the engine light the truck sputtered for a second then the water in fuel light and engine lights went off and the truck ran fine. It did this 2 more times last night, so when I got home I opened the drain on the filter cup as the directions say to purge water. Today while idleing the truck stalled twice, same lights came on then was fine also did it while driving again. I changed the fuel filter a week ago and just now am having the water issues. Today I filled the tank at a truck stop and put in some diesel mechanic in a bottle to clean the fuel system and displace any water, so far no problems, but should I purge the fuel bowl again or could the moisture sensor be failing?? Also are the diesel fuel additives harmful to the injectors or anything and if not how often should I use them and which one??