Im looking to build an aquarium rack on a wall that is 68" wide by 81 high" i can do any combination of 29's 10's and 20 longs. Im looking to breed discus and various small cichlids i was thinking if doing 2 29's up top ...that would be 60 inches across then i can possibly do 3 10's underneath which would also Be 60 inches across or i can do 2 more 29's or 2 20 longs and hopefully squeeze another row in.. How much space should i leave between the top of the tank and the bottom of the one on top? I have the lumber and materials just wanna make sure i do it right...i am leaning towards connecting all the tanks...with a 55 gallon sump underneath any tips suggestions are aprreciaated i am looking to start tommorow