Nice one! How is that workin' out for ya? How much water do you go through in a day's time? I can really appriciate your little doo-dad because I live in a hot, dry, area myself.
What you have there is, basically, a DIY Evaporative cooler - or "Swamp Cooler". So you should benefit from the moisture as well as the cooling effect. It's all good! The faster you evaporate moisture into the air - the more cooling effect you create.
This looks like a really good, basic, model that could use some "Tweeking". Plus rep!