I have been using Diana's recommendations for planted aquariums of quite a few years. I was also fortunate in hearing her talk and got a signed copy of her book afterwords. I did read it and think it is an easy read and informative. I'd not say I follow everything in her book.
Using her method of putting a layer of potting soil or dirt down in the aquarium first, covered with a few inches of gravel and then limiting direct sun light and regular aquarium (low tech lights) I have been able to grow very good plants as long as they are not plants that demand a lot of light. I do have some problems with black beard algae, but no problems with other algaes. But I have a lot of fish in each tank and feed accordingly so algaes can be expected. Water changes once a week.
Both tanks I have set up like that have been set up for more than 5 years and are still going strong. If I vacuum the gravel and am not careful I can suck out some of the dirt/potting soil. Likewise I cannot put in fish that dig. SO there are limits on what you can do and what you put in the tank.
I have two filters on each tank: one HOB and one fluidized bed filter.
Overall, I have been successful with the dirt/potting soil under the gravel/sand at growing better plants than over gravel only.
