Ok then, let's look more closely:
Stocking guidelines have many caveats which are not really covered. As Inchworm stated, you can't just dump a 12" fish in a 12 gallon.
The conversions for volume are quite useful, though there are many sites where you put your dimensions in and it will calculate the volume for you as well as suggest stocking levels.
The marine turnovers are a little strange. It discusses the circulation of an "unfiltered" tank. I know of no one without some form of filtration on their tank. The general guidance is to aim for 20x turnover on a LR only tank and more is better.
As well as suggesting putting salt in a FW tank, it does not point out that brackish and marine tanks require marine salt and that aquarium salt will not do.
All in all I think there are far better sources of information out there, not the least of which can be found on this forum.