How do you change the ppm ...... And what should i...

ppm or ec goes up or down according to the nutrient strength within your medium to raise it you have to increase the nutrient content HOWEVER looking at your plants they seem to be a nice even green in colour so increasing the strength could actually inhibit growth Now they are flowering you should stick to those bloom products you are using but also consider getting a cal/mag and iron supplement to add weekly . kelp products increase root volume which inturn will increase yield so it may also benefit your grow