Try a big dog! Was it IN the water? If so, you need to shock the pool to clear it out.

The smell of chloramines should put the kitty off too. A dilute bleach solution all around the area he left his "present" may put him off too.

Boy, are cats pains in the neck! I oughta know--we have two--had 3 but the old guy passed at 21 a couple of months ago. We've lost a couple over the years, but always seem to have at least two in the house... On the good side, they are always adoptees who need homes.