Just released Predators on to my plants How long before I see a change ?

Hi, So my 2 plants are around 3-4 weeks away from harvest they are outdoors in a pvc greenhouse with a oscilating fan inside . Yesterday I was looking around I decided to look closer at all the weird dots and spots over my leaves, as they had been yellowing at the bottom and dieing quicker than I thought was normal, I presumed it was a deficency but upon closer inspection it was some sort of tiny bugs which I identified as spider mites, they had now progressed to speckling most of my leaves. I cut all the most damaged leaves off and this morning, I just went and brought 3 packs of 200 Phytoseiulus persimilis and put them all over my 2 plants (i hope they went on there) how long till they eat all of the evil spiders because I think they are slowing my plants flowering. Any more info would be great:)
 
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