It sounds like some kind of red algae or mold growing in your water pan or evaporator. If it happened to me I would wait for a break in the weather, take the air conditioner unit outside, remove the filter, and spray Ly-sol or something with fine aerosol mold killer onto the places where you saw the red stuff. Being savy with repairing appliances I would take the cover off and spray the evaporator but don't if you're not comfortable with that idea and/or if it is still under warranty. Some devices are designed with tamper evident seals so removing the cover may void your warranty. I'd also fill a sprayer bottle with water and spray that down in there to rinse it but not spraying into any motors, circuit boards, or visible wire connectors. If water has pooles up and comes into contact with a high-voltage source that is dangerous so be careful to spray water only into areas that you can see.Then I'd let it dry for about 30 minutes, plug it in, and let the fan run.
Then, while the fan is running, you can spray the ly-sol into the area where the filter was and let the ly-sol mist flow through the evaporator. Then leave it run for about 30 minutes to purge any leftover fumes.
Ly-sol is very effective but it is the most irritating substance, to me anyway, to breathe. I recommend ly-sol over bleach because bleach is known to damage plastic. I would not do this inside your home. I recently had a situation where my air conditioner water overflowed and I had to use ly-sol in my room to prevent mold. I think it was closer to four hours before I thought it was safe to bring Kulu back in but I sprayed heavily. I constructed a water level alarm to prevent that from happening again.
Of course you don't have to do this but I think this method will solve your problems.
