Is my Godfather plant OK?

The fact you are now only giving plain water is not relevant, you can not undo over feeding. Once the plant has been over fed, it is over fed, period. The appearance of burnt leaves a week later would be right, as it takes a few days for mild over feeding to show up as damaged leaves. Some of the yellow appears to be as a result of some of them hitting the net and are pretty well typical. Your plant will be ok, just reduce the strength of your nutrients a bit or reduce the feeding frequency. I have found that gentle feeding more often is better than heavy feeding once in a while. Try and aim for a gentle and constant "trickle" supply of nutrients and try to avoid feeding with strong fertilizers that give nutrient spikes. Half strength twice as often is better than full strength weekly (or whatever). I have settled on a routine of, - say a fertilizer says full strength every week, I would suggest three half strength doses over 2 weeks as being more effective and more than enough feeding, rather than the 2 full strength doses over the same 2 week period. Hope this helps, Organoman.