For _jim and rob-woudenberg, you both and myself follow theories of LENR based on reduced volume hydrogen atoms (i.e hydrino, or ultra-dense hydrogen). In my case, supermagnetic clusters cause fusion/fission. Energy can be added to atomic hydrogen via a laser or via electrolysis. All of our views suppose some recombination of the electron and nucleus to new states. Does the production of the new states also produce energy? The hydrino theory says yes and the energy produced is chemical. But UDH and supermagnetic clusters says no. Rather, subsequent reaction of UDH or supermagnetic clusters result in nuclear reactions. The energy states for hydrogen in supermagnetic clusters follow this equation E=n2(13.6 ev). Because the spectra are the same, spectra though to be due to hydrino formation is actually due to decay of atoms in a supermagnetic clusters. A supermagnetic state in an atom will have an associated ultra-dense state. The volume of this state is calculated from special relativity ( i.e the dilation of space-time).
The point is that data supports various theories. Further, electrolysis will produce small amount of nuclear fusion/fission. This I have shown by mass-balance and energy balance of a product call Aquafuel.
I could try to measure oxygen. Not sure about plasma flashback etc., how to detect? I'm not interested in things that cannot be measured
The volume loss cited in this string does not require oxygen to contaminate the hydrogen, if the hydrogen is contaminated with SG gas. SG gas is a magnetically recombined form of water (an isomer of water) in a gas state. A gas state of water that is not steam. It is not hydrogen and oxygen gas combined.
If your intention with water is a cheap fuel for LENR, then maybe an isomer of water, like SG gas, would be a better starting point? I read where the gas product of electrolysis was placed in a paper bag. The hydrogen will diffuse out but the gaseous isomer of water remains in the bag.