Bests & Worsts Reviews from Amazon

I have been using it for a few weeks. I use a fountain without a charcoal filler. I noticed a strange gelatinous substance growing in the fountain. At first I didn't connect that with this product, but after cleaning the fountain for the fourth time and finding this gel every time, I have to blame this product. I cleaned the whole fountain and all of the parts with bleach, thinking that might stop it. It still came back! That "plug" in the picture came out of the tube that connects the pump to the bubbler. It almost looks alive. I bought the Nylabone water additive to save money. It helped with fresh breath, but that gel frightens me. What can it be doing to my dogs' kidneys? I'm going back to fresh dog clean mouth water additive.