Penn Plax Deluxe Bubble-Disk Airstone Aquarium Airstones at Pet Mountain

On October 17, 2012:
I use 8 of the largest size in my Koi pond and they are excellent. On the down side they tend to clog after about two years of use, but that is probably true of any airstone. They provide a very attractive stream of bubbles and very effective aeration to encourage the aerobic bacteria that purify and clarify the water. I am able to enjoy crystal clear water without any other means of filtration.

On February 15, 2012:
When I got this product I was expecting a big airstone that made bubbles. What I got was an airstone with a crack in it and it leaks air so it doesn't even look like there's an airstone there.