I have been using pro grow for 4 weeks and usually stayed within 1700-1900ppm, or 2.67mS/cm. Plants look beautiful. Ph between 5.6 and 6.1 through the 4 weeks. I got got some extra nutrients based upon recommendations but now my PPM is way too high, or is it suppose to be like that? Currently: Using 4 Gallons RO water in 5 gallon DWC bucket, this is how my PPM compounds after each additive. 4 Gallons RO Water - PH 6.4 - 14ppm Cal Mag - 20ml - PH 6.4 - 302ppm Sweet - 40ml - PH 6.0 - 530ppm HydroPlex - 20ml - PH 3.5 - 780ppm 140ml Pure Bloom - PH 3.2 - ppm too high for reading. 3.62mS/cm. 140ml Pure Bloom in 4 gallons of water is 1990pppm. I am using a Hannah GroChek meter and I don't know if it's the .5 or .7 whatever conversion.
Dude! Am I reading this right? You said your PPM is between 1700-1900? You're lucky your plants aren't looking like a chicken leg from KFC. At the very most you should be using 1200 PPM, and that is in the later stages of flowering. 4 weeks in you should be around 500-700 IMO. With the bloom you shouldn't be using more than 25-30ml per gallon.
I've never used that type of nutrient, but in a 5 gallon bucket you're putting about 3-4 gallons of actual water in. And you're putting in about 9 tablespoons of nutrient in. I don't think that can be right, but like I said I've never used it. Either way, I think the answer is clear, cut back on the Pure Bloom. You should sit anywhere from 1000-1500 PPM depending on the strain so take it easy some on the nutrient and your PPM should come back in range.