Well, Mazzei injectors are basically industrial gas/chemical injectors made by that company. There are other brands, but these were the first to be used on a large scale basis. They are basically a venturi and work the same way as a carburettor, lowering the pressure at the throat which pulls the gas into the flow stream, allowing a highly saturated mixture of water and gas at the exit. They are so effective that they can pull the pH down in a large tank by one unit in about 20 minutes, but there are several requirements;
1. You need a fairly strong water pump to push through the injectors to get sufficient pressure drop. External pumps, made by companies such as Iwaki or Magnum are commonplace here in the states but not so available in Europe.
2. The sizes of the injector and piping is critical for efficient operation.
3. Special fittings are necessary to connect to the the injectors.
None of these problems are insurmountable, but it's just that one has to do a lot of homework to figure out the schematic, to get the right pumping power and so forth.
Here is a typical connection scheme. The injector is that black pencil sized object at the very bottom middle. Water flows through the two horizontal white branches with a flow control valve at the top. In the middle of the injector you can see a connector for CO2, which fits at the throat of the venturi.
Here is Mazzei's homepage =>
http://www.mazzei.net/products/typ_install.htm
Really, this system is serious, and it's only for large tanks, i.e. 100G and up because small errors can result in gangland style execution of the fish in no time flat baby. Mazzei is strictly for the unrepentant Don Corleone CO2 Mafioso (like me 8) ).
For more data check out The Barr Report and search using Mazzei. You'll find tons of info but it can be bewildering. Here is a good thread to start with: =>
http://www.barrreport.com/showthread.ph ... azzei-Plan?
Cheers,