Say what you want about needle-wheel skimmers. They are efficient at producing bubbles but what if you want to inject something other then bubbles? Mazzei venturis are a great choice because they allow you to inject any liquid or gas into the water itself. They are more commonly used to inject air, ozone and oxygen. They are made out of PVDF kynar and if you install them properly they can transfer ozone into water with efficiency ratings as high as 99% . These venturis include a 1/4″ barbed ozone safe check valve and operate at a maximum pressure of 400 psi. Pricing starts at around $60 for aÂ 3/4″ Barb, 3 gpm, 4 cfh model. Most specialty stores might not have these in stock, but feel free to inquire about them.