My plants are not getting redder?Updated 2 months ago

While nutrition plays an important role, pigmentation is dependent on many other factors - light, CO2, temperature, and horticulture methods.  

Light intensity and spectrum are both extremely important. Check out this post for more details.

For picky species, CO2 levels have a big impact. Check out this section on how to improve your CO2 injection.

For species that require Nitrate limitation to become redder, Check out this section.

APT 1 and APT 3 will work to redden species that require Nitrate limitation to be red. However, APT e will not work for such species, as it contains a lot of nitrogen.

For species that require deep nitrate limitation to turn very red, such as Rotala rotundifolia variants, adding APT 3 may cause them to initially lose their red color - as APT 3 does contain some nitrogen. As the tank matures on APT 3, the red coloration should return as the tank becomes nitrate limited over time as plant mass increases. 

In tanks where there is ample source of nitrogen, and nitrate limitation is needed for certain species, then APT 1 should be used instead of APT 3.

Nitrate limitation sets in as plant density increases and uptake rates for the tank rise as a whole. APT dosage can be varied by checking the coloration of the newest leaves. Greenish leaves on previously red plants can be a sign that nitrogen is plenty, and less fertilizer can be dosed.