In the basement of my house (outside entry with 5 foot ceiling) I have a slab concrete floor that used to be dirt. In really bad rain it isn't that uncommon to get a bit of water of some parts of the floor.

I've been noticing a white fuzz lately on the concrete floor. I'm told its not mold but I'd like to get rid of it because I'll be selling the house next year. I don't want others thinking it is mold when they come to see the house.

First.. what is it?
Second.. how do I get rid of it?

I already tried a bit of bleach and water but it grew back within two days and seams to be stronger.. I'm thinking painting the floor with a concrete paint might be a good option?

I installed a dehumidifier this week to try and get the humid down after it rains.