Ok, with my British sense of humour let me try a less “joke ridden” version.
The feeding and growing of Flowerhorn is pretty well covered by many “experts” and certainly people who know a damn site more about it than I do, that I can vouch.
However, over the last 44 years keeping tanks (lots of tanks at any one moment) I can pretty much say that 10 hrs a day of decent lighting grows algae pretty well. Better if I don’t have a gravel or sand bottom with plants to remove excess nutrients, nitrates and phosphates.
Brown diatom algae is a frequent visitor in the early days of new tanks and often goes away by itself, but one way to get rid of it is by increasing lighting, but I would say safe to suggest that’s not why you have it.
Glasgow water I would expect to be soft and whilst it could be phosphates, I would probably suggest more likely silicates in the water.
As for the hair algae , that I would expect to be more phosphates based and the amount of lighting with nothing to use them up.
Equally, in my marine tank I have to adjust which light I have and in which amount as certain colour spectrum grow algae better than others. So not only the amount of lighting you have, but the colour / temperature range will dictate if and which algae grow best.