I’m having some trouble figuring out what is going on with my aluminum floor.  I have these small starburst-like pits in the floor (See photo album by Clover1 – Trailer Floor).  I do not leave manure in it after a trip and the horses have never even urinated in it.  I bought it new, a little over a year ago and have used it less than ten times.  The pits are at the head side of the trailer, not at the horses' rear – ever odder.  I have washed the floor (flooded it actually) with water three to four times, and let the floor and mats dry completely before replacing them.  Up until the last time I washed the floor, maybe six weeks ago, I have kept the mats rolled back off of the floor.

I contacted the manufacturer about ten days ago and sent photos.  The rep that I spoke with said he had actually never seen this before.  He didn't know what was causing it, but said it was nothing to worry about, based on the way I take care of the floor.   

I’m having a difficult time accepting that it is nothing to be concerned over, if the cause is not understood. 

I purposely have not included the trailer manufacturer.  I’m completely satisfied with all aspects of the trailer, except for this issue.  Has anyone else experienced this problem with their floor?

I was surprised that the manufacturer of your aluminum trailer didn't know what oxidation looked like. The rep you spoke with may be new in his field of endeavor.

Oxidation should be treated and not ignored. To do so will only allow the area to further deteriorate, just like rust does on ferrous materials. If allowed, the holes will continue enlarging and eventually penetrate the aluminum thickness.

The spots have to be chemically treated with a weak acid like muriatic. You could treat just the spots, but if these are found within a non urine area, then it sounds as if the installed metal wasn't properly treated,  particularly in light of your cleaning procedures. I would do the whole floor and know that it was then properly conditioned.

BOL  Gard.

Look in here...  http://www.horsetrailerworld.com/forum/photos/photo-main.asp

Here's the pic. ... http://www.horsetrailerworld.com/forum/photos/photo-thumbnails.asp?albumid=131