In theory, yes. In practice, a bit inconvenient.
You’d just buy a 1/4” barbed Tee (or Wye) at a local Automotive Supply store and connect it to the output of the Drinking Water Bubbler with a short piece of 1/4” ID vinyl hose.
For optimum effect you’d need to (for the first 15 minutes) synchronize your breathing so that one of you is breathing out as the other breathes in. This assures both of you are getting the full HydrOxy flow.
After 15 minutes your blood should be saturated with hydrogen and you’ll be breathing OUT almost as much as you are breathing IN. This is one of the reasons there’s no toxic limit. The body ‘knows’ to exhale any excess.
It WILL WORK if you both just breathe normally, but it’ll take longer to saturate your blood (both of you) because sometimes you’ll both be inhaling and the hydrogen flow will go to the one who is inhaling most (usually the man because of larger lung capacity).
Once the blood is saturated, it only taskes a small amount of hydrogen to maintain saturation, so two ’saturated’ people shouldn’t have any issue maintaining saturation for the remaining duration of the treatment.
When breathing together, the gas volume (Duty Cycle) should be set at the setting for the SMALLEST person, because there will be times the (usually she) is breathing in when (usually he) is breathing out, and she’ll be getting full gas volume.
Can I split the tube upstairs with a Y connector so that we both can inhale while sitting in the chairs watching TV?
Yes.
If that should work, do I increase to perhaps 80% or 100%?
NO! Adjust the gas flow to the % of the smaller person, because sometimes s/he will be getting the full flow.
Whenever a person exhales, they create a back pressure that prevents the gas form coming out ’their’ tube and when they inhale they create a vacuum that draws the gas to them.
So whenever one person is exhaling s/he is ‘driving’ the gas to the other person and (assuming that person is inhaling) s/he is sucking the gas toward her/himself.
The gas always goes to the path of least resistance.