The reason for the very strong ammonia smell in a cat's litter box is unchanged litter. Many times, one fails to change the cat's litter and this causes ammonia to get concentrated in the sand or clay used as litter. You may find the litter clean, but the smell of ammonia seeps into the sand or clay. This causes the smell to get stronger and awful. A litter box should be scooped out daily--it really should be done for both behavioral and medical interests of your cat. (Have one box for each cat). If you notice your cat scratching outside the litter box instead of on the inside, the cat is trying to tell you that the litter box is disgusting and it doesn't want to get its feet filthy while "attempting" to cover up it's feces/urine inside. If you just cleaned the litter box and it's still doing it, it's likely from a bad memory of getting its feet urine-soaked or dirty while in the box, so unless you want a cat that defecates in random places, get in there and scoop. The other added benefit of scooping frequently is that it helps you detect medical problems earlier.
By its very nature, non-clumping litter does not absorb and isolate a cat's urine or feces like clumping litters do. As a result, it is much harder to keep your cat's litter box clean when using non-clumping litter. When using non-clumping litter, it is important to frequently clean and disinfect the litter box itself to reduce the chance of bacterial buildups that can cause urinary or other infections in your cat.
Some cats will "hold it" and urinate as infrequently as possible to avoid stepping into a dirty, filthy, full litter box. Instead of urinating two to three times a day, your cat will tighten up and only go once a day. The problem is that this makes his urine more concentrated, potentially resulting in crystals (even debris, mucus, pus, or stones) to accumulate. This can then result in life-threatening feline urethral obstruction (FUO), which is when the urethra is blocked and urine can't come out. Not only is this painful, but it can also lead to temporary kidney failure, electrolyte abnormalities, vomiting, lethargy, arrhythmia's, and death. Cleaning helps prevent problems like this or even diseases.
Professional Pet Sitting Services offered in the Upper to Mid-Pinellas County Area