No fertilizer ever used. We have had a heavier rainfall than normal this year and cooler weather.
Here in the Midwest after our drought broke and rain came, the algae problems really exploded! I could only theorize that due to the very wide geographic coverage of unusual and heavy algae outbreaks where it had not been before, the decayed matter in watersheds, such as dead grasses that had succumb to the drought washed into the ponds and overloaded them with nutrient.
I suspect the recent rains in Texas and Oklahoma will cause the same situations.
