I agree with Amtiskaw, though I do use one of them on my smaller tanks Cam. The only issue I have with an inline diffuser is the restricted sizes, all fine if you're using a pump with the same size hose but if you are like me and are using a filter/pump that uses large return hoses you have to rig up some type of reducers to be able to plumb one in which causes a lot of reduced flow. Only issue I see with using one on a 750ltr is making sure the flow is enough to make the co2 reach all areas of your tank, and maybe if you don't like seeing your tank look like a bottle of highly carbonated lemonade lol.