First off you can't technically lower your PPM of EC (emulsifiable concentrates) without totally changing out your water, which is OK if you screwed up on feeding. Which is why hydro is a blessing. So If you want to lower the PPM, dump the water out and re feed and treat the pH of the water. I would stay around 6.5 pH, but that's my opinion, everyone has one.
I'll go against the grain by saying I don't bother with this pump it up to so and so rate of feed 6 weeks. Into veg growth or whatever. Again my opinion, I'd run no feed(40-100 "PPM" if your using distilled water... Non distilled water has minerals and salts already in it) until the girl establishes herself, seriously depending on what cultivar your growing but usually 6-12 inches in height with decent leaf expansion.
After such established point in her life time she Will get hungry. I encourage you to run the rate of no feed to see the effects of "yellowing" don't worry, just add feed and she'll green right up. Even add Fe to impress your friends with the color. Anyways, I would run 300 PPM of feed for early vegetative growth. Ask yourself this question.. Where do plants in nature find a random spike of nutrients within the soil they anchor themselves too? They are born to look for such nutrients through long periods of time and use what they are given very efficiently. Bombarding your media with nutrients won't do anything for your plant except stress it out. Sure, you may cut back a week on your grow time, but I bet the quality isn't as good and you'll run into more problems.
I'm starting to ramble because I should be writing a humanities paper but one last note, every PPM meter measures differently so it's not very accurate to share what you are doing by reading off your PPM meter. Also make sure you calibrate your meter everyone once in awhile.