Ultrapure water this sort of says it all, what we use is filtered water nothing else and the only reason its filtered is so that
it doesn't leave the removed solids on the glass.
It doesn't clean any better or do anything that unfiltered water couldn't do.
Heres a question CleanClear, How do filter tap water at 300ppm without boiling it or using any filtering equipment ?
Answer, pour a litre of it into a 600litre tank of 000ppm pure.
You see the dissolved solids in the water are still there but have been diluted to level where they no longer cause a problem.
The same can be said about the solution you added to your water, its still there but its now diluted to a level where its not going to make any difference to the cleaning power.
When you mix your HG window cleaner at the correct levels to water what you actually do is turn the water into a cleaning
solution, that's what a concentrate is designed to do.
Hi Sean, i'm a little confused understanding your post (its probably just me). I agree tossing a litre of unpurified water into a tank of pure will make little to no difference. If i've got you right then you say tossing a few milliliters of cleaning solution in a large tank like 400/600 litres will make no difference to its cleaning ability ? I'd of thought the same. I'm also suprised at how it bubbles and froths i wouldn't expect it to do that either. I done no measuring at all, i just squirted a squirt 
Like what you'd do for your dishes in a 350 litre tank. Wether it cleans any better i've no idea. But what is clear is that it cleans at least the same and seems smoother.
If it can produce so many bubbles at such a low concentration, what other effects can it bring that you might not see straight way? Like the surfactant effect whereby the water retreats and "dries out" away from edges and seals ? Who knows? Thats what i'm gonna try this week.
The point is just to show how little of the stuff your actually putting in the water, the thing is it doesn't matter how many
bubbles you get it still only a cleaning solution in a very weak mix.
Take some out of your tank trad with it and see if you find any difference to it and water on its own.
Take GG4 for example, it doesn't even restore the shine on upvc in its recommended mix and that's with it leaving a slight
coating still on the frames.
You talk about glide, well if you want more glide then use an Xtreme brush you see that's the thing more glide means less grip
scrubbing power.
