Well, 75-P is not really a cube, it's 30"x18"x18"...
That aside, the proportions are personal preference.
That aside, the first rule is: larger is better. I personally would go with 36"x18"x18" because the proportions are more pleasing to me and the 'extra' 8g can go a long way. The 36" is almost the same as the 40 Breeder which is one of the most popular sizes for planted tanks..
That aside, there are a lot more choices in 36" lamp fixtures then in 30" fixtures.
In the ideal world, I would shoot for the ADA's 90-P
, which is one of their most popular tanks. But money does not grow on trees.
So, let's see, the only place that I know where you could possibly get Mr. Aqua in the BA is Albany Aquarium, and only if you call ahead and sweet talk them into a special order, and that's a long drive. The other option is online from MarineDepo
, add $100 shipping, and now you are at $390 vs ADA's 75-P at $330 with ADA's 90-P @ $500. That's a $110 to $170 in the hole.
It might be worth to you to make yourself a present and to cover the difference.
Or, you can always call AFA in SF, talk to one of the brothers and see if they can make you a deal (they did for me).
It so happens that SCAPE is planning a group meeting at AFA this Sat. The meeting is closed-doors with a presentation from the owners on their trip to Japan, after which the attendees will have the run of the shop. I do not know, but there might also be some 'special pricing'... PM if you want contact info.
Drive to SF, meet new people, spend the night in the City with your BF, pick-up a brand new ADA 90-P ... Life is good.
On the other hand