Also, regarding those Oxygenics shower heads. Although they may be able to save water if used carefully from injecting air into the water stream and from turning them ON/OFF while showering (Navy showers) - they may need a higher flow-capacity water pump to perfrom their air injection process better.
We have an Oxygenics and I wasn't impressed with it's "shower comfort" (I haven't yet measured it's water usage improvement). I've since installed a high capacity pump in our RV to see of the Oxygenics shower head will actually "save water" through more efficient air injection, while at the same time provide improved shower comfort.
It sounds counter-intuitive to install a higher capacity pump to decrease shower water usage, but we'll see what happens with better air injection. I do know that the higher capacity RV water pump sure makes using the kitchen sink faucet a lot nicer and may actually save water there, to ... because it needs to be "ON less" in order to rinse stuff off.