Do your fish seem to be doing ok ? Do you have alkalinity and DO numbers? Don't add any fertilizer for now and if possible run the geese off. You need to be careful. If you are pulling up low o2 cold water from deep in the pond to surface you could cause a DO crash if it kills your bloom. Some surface aeration at night would be good. If your fish are ok then your biggest risk is if your bloom dies and causes a DO crash.
You may be ok if DO is good. What about water temp. profile. The fact that you have low visa. and green water will not kill your fish as long as you have good DO.