Fertilizer Question????

you do not get algae or many issues for adding ferts, they can indirectly affect uptake of CO2 (generally increasing it), and when that occurs then all hell breaks loose with algae. going from high or moderate CO2, to low/very limiting levels, or stable levels to non stable levels seems to cause the most issues, in CO2 and non CO2 enriched systems.

Historically, many have blamed nutrients, however, simple test that falsify such claims show there's obviously some other mechanism causing algae other than nutrients.

CO2 moves around quickly, and algae appear to response well to it.
Where it's stable, then the plants adapt and do pretty well.

Regards,
Tom barr