I hadn't posted pics, but here they are now below. In any case, this is a new and unstocked tank, which had a host of invasive nasty algaes come in on the liverock I received. So there is no livestock whatsoever to worry about.
I started by dosing 1 ml of 35% 2(HO) per half day day, which was apparently already 4 times the advised dosage for systemic treatment, and then expected to keep increasing the dosage by half until I saw immediate melting. And I just dumped a full 250 ml of 35% into my 34 gallon tank and hour ago and am seeing plenty of bubbles but still no melting yet, (of the tank or the algae).
I have a bunch of dry rock rubble glued to the backwall, which has algae and is why I don't simply wish to remove and dip the rocks.
And my assumption is that the spores of these algaes are everywhere throughout the tank including the sand, walls, and filtration. Therefore, harsh system dosing is still an option being that my tank is unstocked. For otherwise it will just return later on its own.
Adding a quarter litre of 2(HO) just brings the overall tank water up to a concentration of less than 0.1% hydrogen peroxide, so I'm not sure if I'm expecting that to kill anything really, not least every last algae cell. Maybe if I did ten times that dose, with 2.5 litres of 35% to bring the concentration up to about 1% then I might start to see some real melting?
Here is how it looked earlier before I'd been weeding it by the handful and when I was having a bit of die-off on my live rock.
And here is how it looks at the moment still after heavy Tech M and Magnesium Peroxide treatments already, (with annoying reflections). -