I have 2.3..the males have ~ 10" and the female 11-13,5".
The filtration is called in Germany "HMF"...I dont`know the english word.
...it`s only one filtrationsmat in the left and right corner with a powerheadpump behind them...there are also the heaters.
It works since ~ 4 without problems....
btw you have a very nice avatar...wat`s the name of this sp. of Leopoldi...Bd-eclipsed-thousand island-leopoldi