That cat pee thing happens in my brute too. But no ammonia. I think I am going to get another 40 gallon water container to replace the brute.another thing i forgot to mention, another reason I got rid of the mixing station was the saltwater barrel (even after cleaning it out) smelled like cat pee. Thats the best way I can describe it. And the tank water smelled like it as well. So I thought maybe ammonia was somehow getting into the tank. But i've read other posts of users making the same statement with no ill effects. Still got rid of the mixing station anyway as a precaution. Again i went back to my white food safe buckets.