If you want a slow growth tank, this is a good way to do it, obviously he gets good reds, health etc at 2 w/gal, but sooooo many folks whine, cry, kick and have hissy fits claiming they need more, in the 4-5w /gal ranges.

I can grow nice gloss at 1.5-2w/gal.
Things are easier to grow well over time, not faster.

Less light allows more wiggle room on any fertilization routine you might have.
In some the books, he routinely has extremely suspicous similar parameters for every tank. If you test over a 24 hour peroid and then test daily over a week, these parameters change a lot more than that.

They are fudging the data or they just did a big water change right before they took the photo and then tested the water column.

There's just no way the test would come back with 0.1ppm of PO4 for every tank, or less than 10ppm, that shows a cheap, poor range test kit for both parameters.

CO2?
In some tanks he uses inert ceramics/sand etc, yet has 23ppm of CO2 with a KH/pH of 2 and the pH of 7.0. Other similar tanks have the same pH/KH and the CO2 is 13 ppm.

I'd not put too much weight on the water column parameters.
CO2 added to a low light tank works very well.
L:ikewise, if you want very low water column ppms, a non CO2 tank is the best option over time.

Regards,
Tom Barr