Settle down there Simon, I might crack a rib from laughing so much. Seriously though, I get your point about attractiveness being subjective. That said there is a reason why certain tank proportions are popular. Inserting this into a wall further complicates it. I think I'll just build a cardboard mockup to get a better sense of the space.
I suspect what you are thinking of the the Golden Ratio, which uses a series of decreasing rectangles to a specific mathematical ratio of ~1.6:1 :-
It is well documented that humans, for some reason, find objects and compositions that fit well within the Golden Ratio to be the most naturally attractive and balanced, and there are a great many highly attractive things both man made, and occurring in nature that conform closely to the Golden ratio - it's a fascinating subject all on it's own, so probably a discussion for another thread.
One of the most common tank sizes, the 60P size made famous by ADA is 60cm x 36xm; 60/36 = 1.66, Though I don't know if that is by chance or design.
Rather than the tank size, though, its the application of the hardscape layout that will determine whether the composition fits within the Golden ratio - should you decide on that as a valid design objective, so at 1800 x 500 for your tank, you should be fine, you would just need to use multiples of the golden ratio, like this - this is one of my favourite longer tank layouts by Dave Chow:
Which very closely fit the golden ratio:
Arguably even with a third central overlay it fits even better:
But then it also works to the rule of thirds also:
A lot of artwork seems to fit within the Golden Ratio also, and a lot of artists naturally settle on a composition or design that just looks 'right' to them - so I suspect they don't intentionally try and get things to fit within the Golden Ratio or rule of thirds, it just ends up that way. Indeed if we look at
@Konrad Michalski hardscape competition winning entry from last month - maybe Konrad can confirm if he intentionally used the Golden Ratio, as the design fits very well:
For those of us without that natural artistic ability (and I include myself in that) the rule of thirds and the Golden Ratio can be useful to help choose focal points or break up a hardscape design into sections. Ultimately though its not a hard and fast rule.
Sorry for rambling here - it's just been an area of interest for me recently as I have been wrestling with ideas for my own new 1500 x 450 tank.
In terms of your tank, think of practicalities too. 1800 x 500 is a large tank, if you make it 850 wide too, then is becomes a very large tank - that's 765 litres, so a 382 litre water change each week. Maintenance will almost be like maintaining two 1800mm tanks. Personally I'd go narrower at around 600mm and with an island style design, you can create contrasting views from each side with some careful planning.
)
