Gosh MW, I was looking at that and thinking WOW, she really goes for BIG tanks to recommend to beginners!!
And, thinking about it (as this topic comes up again and again!) I sort of went off on a tangent thinking about how, in the end, the individual and/or the individual situation of the individual is just so, so, very unpredictable that it sort of defies anything close to a final size recommendation beyond a few maxims, right?
Clearly, one of the most important guidelines we can impart to beginners is that as the water volume gets larger, the water chemistry sides of the system will get more stable and easier for them as beginners. Very small tanks are very tricky even for experienced aquarists, and sometimes a nightmare for beginners. But here I think we're talking less than 10 US Gallons, or perhaps some would but it at less than 15 US Gallons. Anyway, somewhere between 10-20 US gallons (that's between 38L and 76L for you Brits!) must be where the turning point is between a tank that's too small and tricky, or one big enough to be much easier to learn on.
Not so clearly, the top end seems much harder to me to make recommendations about. MW's comment, putting the top end for beginners up at 100G is described with some care, which is good. It indeed must be true that some things like filtration and floor reinforcement begin to get more exotic when you get up above 100 US gallons.
Gosh, its just really a hard call. The tanks between about 55G and 100G would be really stable (chemistry/biology wise) and so, great for beginners, and its true that if it turns out you love the hobby, you would be so glad you went all out and now had such a beautiful big tank... but on the other hand they are so BIG! If you found you didn't have the patience for the maintanence after a few months, it could be a lot to handle and a lot of expense. I don't know, I probably should learn to be a bigger risk taker, but I just still feel that the sweet spot for beginners is more in the 15 to 40 gallon range, with 28 to 40 or so being the sweetest of all.
But I'd still say the upper end varies wildly with individual situations, whereas the lower end, the minimum is clearer to state (don't really want to be going below 15G or so if you can possibly help it.)
Gee, that probably cleared up nothing, right?
~~waterdrop~~