Here is some info on HHO Gas qualities, ALL MADE FROM WATER :

Levels of Gas atomic quality:

TOP quality first : 

TRITIUM Gas 3H (From radioactive HHO water, not safe, but the most powerful gas on the planet!  SHOULD BE AVOIDED AND NEVER MADE!! )

DEUTERIUM Gas 2H ( Gas from HHO, Either gas or water will run a ICE engine) This gas is 'classified' by the US DOD and your not suppose to know about it or to make it ?) If you make this level of gas, you can get a ICE to run off of it. Stan and Stephen Meyer and Steve Ryan, Bob Boyce all experienced this form of gas. If an inventor sends off a patent request to the patent office, they will gag order this form of HHO gas, buy them out, or tell them your threating National Security. If you take the cabal's $, you become apart of the cabal. The next choice is death to you and your family, unless the Lord Father wants to keep you alive for other reasons, they can NOT be taken out. Holy terror is experienced by the assassin and he flews in total fear or dies on the job and has to meet his maker now.

ORTHO HHO ( this HHO gas is can be proven to be 4x's more powerful than PARA HHO) This form of HHO gas can not be pressurized past 10 to 15 lbs, it can self spark back to para HHO and blow up your cell or water tank or bubbler or dryer filter housing. For safety we use a 5lb. pressure safety shut off switch.

IONIC WATER VAPOR ( This form of HHO goes above para and clings to the hydro carbon well, but the cell gets too hot and the water tank or cell has to be flushed and maintained too much labor and the electrodes will erode fast or slow, depending on your "voltage leakage and how well sealed the cell is. Open bath systems where the electrons can jump around the neutral plates or tubes. This is where guys pressurize the HHO gas and enter the EXPLOSION ZONE, dangerous as all get out. Though Yull Brown said he can safely pressurize some forms of HHO, I would stay FAR away from pressuring the HHO gas. For many years I made a cell that produce ionic water vapor and got MPG gains. I pulsed the DC with a square wave pulse and the cell worked best at 120f degrees. It needed cleaning too much and maintained and experienced the HP.

PARA HHO - (common hho) A form of HHO spilt from water, where the H shares the proton, the H's are still connected. Not the best for HHO boosting with gas or diesel as it can pre-detonates the engine. The para HHO gas bounces off the other air borne molecules and bounces off the hydro carbon chain of molecules. Sorry to say, this is what 90% of all HHO cell builders make, even the ones funded by the Oil Corps, to try and disrupt the HHO market and to rip off all their customers on purpose or no real research, just a copy cat company wanting to sell the next best green thing. Young men having fun in their garage and your buying their experimental project. They have the right intentions, but a little green under the ears.

STEAM, steam has lost most of it's combustion power. ( not talking pressurized steam, that is totally different subject ) 

HHO Gas and Hydrogen Injection Studies

HHO Garage