In 43 years of fish keeping I have owned and repaired many pumps. This produces 2800cc at a high pressure. I have one running 2 years in 24" water, and it will run 2, 12 inch airstones. The valve body is centralized and so far the diaphragms are good. I hope tetra is using better rubber because all the whisper pumps I owned in the past needed repair every 6-8 months like clockwork. Well at $0.99 it used to be cheap to own a whisper air pump. Today the repair kits are $6.00. This Aquaculture pump has had some bad reviews, surely any pump will fail if you don't have a bleed valve to let off exess pressure. Although I run 12 inches of air stone at 24" of depth I use no bleed valve. I clean stones in vinegar monthly, and replace when I can't blow through them by mouth. This is the most trouble free pump I have ever owned, Sorry Tetra you Whispers don't compare.