ok if you really want to do somthing usefull,
Then design a piece of software that allows you to design the tank from scratch, you could have a whole host of stats involved, I.E if you select a certain fileter it tells you the tanks turnover etc etc and this could be done for any piece of tank equipment.
Then you can have a stocking list as you select each species it then eliminates any un-suitable tank mates.
no one has managed to put together a complete tool, also the tank set-ups could be shared online to then allow noobs to pick a tank and know exactly what filter,heater,fish etc etc to buy.
Pimp-my-tank.exe