Having folks learn how to use CO2 right is hard, no chart is going to make this clear.
And the java fern in Hani's tank has CO2 issues.
The old leaves will not recover, may as well trim them off and wait for new leaves.
The Anubias, I've seen this before, but hard to say, could be some ferts in dry form hit it, something else burnt the region, many other potential things other than just ferts of CO2.
I have some SERIOUS ISSUES with this chart, the 1st thing on Deficiencies has has been falsied is frankly RUBBISH.
The Mg and K+ quackery has no business there.
These are myths and the chart only helps to reinforce this myth further.
I've yet to see a single confirmed case of Ca Deficiency in 15 years, and it is not from a lack of looking.
I've NEVER seen yellowing due to PO4 deficiency.
I can go on and on. If you do not know, just leave at that, and make it clear it is an unanswered question........do not GUESS then say you know when you really do not.
Some parts of the chart are good, but many others are misleading at best and some are outright myths.
There is little discussion about O2 with respect to CO2.
And as Wet is aware of, little about lighting.
I'm going to be particularly harsh on these charts, since many love and cling to them.
If there is uncertainly and evidence that contradicts it, I'm not going to back down.
I've tried for over 10 years to show that the K+ and Mg business is real, never have I been able to confirm ANY of it.
I have on the other hand, falsified it multiple times in multiple tanks.
Simply claiming the myth over and over will not make it fact.