If I can lock down what causes the blue/green cycle to break down, I will. It may take a few weeks to confirm what I'm watching every day. Multiple cows in a huge watershed pounded by spring rains is what always causes it, but low rain totals don't hurt my pond as bad. 2 of the 4 cycles have been problematic, but little, if any, loss on any of them.
That spoiled little Nubian turd. He went from the outhouse to the penthouse and knows it. Vanilla wafers are his treat of choice.
FIH, concentrate on observing water temp and N/P ratios. (the latter would need accurate water tests to track the levels).
Only way to stop the cycle is to keep the water from getting to the temp where it loves to grow and/or keep the N/P ratios below where it likes.
If my memory is correct, it loves 20:1-25:1 N/P ratios, and still grows in water that has a 30:1-15:1 N/P ratio. Get the N/P ratio at or below 5:1 and it will have a hard time growing. That's why nutrient mitigation in ponds is so critical. I'd have to dig into my notes to be sure though.
Bacteria works on the N aspect, Aluminum sulfate/PhosLoc works on the P aspect.
