Zep toilet bowl cleaner
Your review: I used this on rings in toilet bowls at our condo at the beach. The water is very hard and the rings in the toilet were just impossible to remove. It took a couple of treatments of Zep because the buildup was so great but the rings are gone! Great product.
Pros: Easy to use. Does not require lots of time.
Cons: I have no negatives for this product.