VIVOSUN Air Stone 2PCS 4 X 2 Inch Large Air Stone Cylinder for Aquarium and Hydroponics Air Pump

These are tough airstones. I am amazed that they still work at all after the beating they took in shipping. Bashed so hard, they were knocked free of the factory cardboard packaging. Some chips were knocked loose. Amazon put these heavy, brittle stones in an oversized, non-padded plain manila envelope. That's no way to treat airstones. Isn't Amazon supposed to be in the shipping business? Fail.

I've tried the VIVOSUN, Pawfly, ActiveAir, and an assortment of smaller variations (I learned after a while to stick with the 'pop can' versions for DWC Hydroponics). The VIVOSUN stones seem to distribute the smallest, finest bubbles over the greatest area. I commonly use one stone per bucket, but I recently ordered more and added two per bucket. Growth has exploded. I didn't really expect it would make much of a difference and I just wanted to make use of an extra air pump I had, but the results are undeniable. So, in short, order a few extra and double down. At this price you can't go wrong. Noob note - never wash with soap and the put stone in reservoir. You will be giving your plants a bubble bath. Soak stones in ph water before use.

Expected a little more from these considering the size (I bought the combo recommended pump and everything ) No huge deal as I have one of these in the bottom of my hydroponic setup and a smaller more bubbly stone suspended closer to the root zone of plants.

Another vivosun produced added to the collection.

Bought 3 of these and using them in 5-gallon buckets with a 20w commercial air pump. They work exactly as expected and well-constructed (the barb and the glue that holds the barb adapter to the stone). Very satisfied with the product.