We would annually pull the mats and wash out the interior. For the past several years, we've neglected to do that. Just today, we pulled the mats and power-washed the floor and found several small holes, the size of a beet seed, as well as other disclored slightly raised areas. We had corrosion. We pressure tested the aluminum around the holes and the raised areas and there's still significant strength of the aluminum. When we had the trailer custom build, we had the cross memebers set a distance of 12 inches apart, so I'm not that concerned the floor will buckle. The mats adds further strength to the floor when they are installed. My question is how to stablize the corrosion. Horse urine off-gasses ammonia which is a base, which would indicate you'd stablize the corrosion with an acid, like muriate of acid. Yet another web-site said horse urine is highly acidic, which would indicate you might stablize it with something as simple as bicarbonate of soda (actually recommended in general for corrosion of diamond plate aluminum). Has any one out there had any experience with stablizing aluminum corrosion due to horse urine. Thanks.