Anyone here use liquid Kelp as a foliar spray on their citrus & fruit trees? Any dos and don'ts?

I got a large gallon of liquid kelp and fulvic acid and I want to use it as a foliar and root fertilizer for improving yellow leaves on citrus and making my fruit trees more resiliant to pruning and grafting cuts. I see people are using it both every week and every other week.

How long before you notice effects like yellow leaves reversing on citrus trees via foliar spray? Should I only spray only while new leaves or new fruit is setting on the fruit trees or can I spray year around until the leaves fall? Anything else I should know?

Are there any health risks to getting some of the spray on your skin?