Review on Aquapapa 4X Dual Bio Sponge Filter for Betta Fry Aquarium Fish Tank - Up to 30 Gallon Capacity - Ships from California, USA by Kimberly Sanders

I'm so glad I have these babies. You work so efficiently. I have used them in my bettas, mollies and guppies. I have some advice for those who are thinking of buying them. A NOTICE. These sponges are denser, so using an air pump that isn't the right size for your aquarium will cause problems. - Due to their density, they gain more. This means you may need to wash them more often. If you notice your blisters aren't coming out evenly, perhaps gurgling, that's an indicator that you need to flush them out. ** Sponges should always be rinsed out with aquarium water. I suggest doing this when you do a water change. I use buckets, so before I pour out the buckets, I remove the sponges: I rinse, shake, squeeze them into this bucket, and put them back on. This helps keep your BBs (beneficial bacteria) in your sponge and doesn't introduce heavy metals and the like (from the tap). Your fish and plants will thank you. Plus, you won't waste water or make unnecessary trips to the sink. ;)