This is a good references for me as well, since i am intending to have a similar 6 footer as well for my new place soon.. :eyebrow:
However, i feel AB6000 may not be enough as the main return, you may need a 10,000 litre flow/hr at least.. further more, IMO i feel smaller version of the AquaBee pump like the 2000, 3000 and 2000i ect work better but for the larger series, the performance is not as good as compare to other brands as the performance seem to drop very quickly..
Show some photos of your sump setup as well lah...
can PM me the contact for the tank maker and the cost ?