This is so key IMO. You could flood your tank with co2, but the plants especially in an Iwagumi are only going to do so much, so you need to support the bacteria and keep the tank extremely clean organically. Carbon, purigen, etc are really good when the bio-filter is just too immature as well some of the ADA product or using other methods. Unfortunately I think too many think of co2 as an algaecide. It's really limited to plant growth and mass, so in an Iwagumi as well as at startup it's not enough.
You've got exactly the right mind set my man! See post above.
P.S. if you've found these techniques valuable, help share the information with new comers by linking back here in your own journals when you use my techniques!