That they have plenty of nutes and are drinking up more water than nutes.....that is normal and usually why they recommend topping off at 1/4 strength nute solutions and such....to help readjust the balance. Keep in mind though that your ppm number does not reflect percentages....ie...did they eat all the phosphorus and leave the potassium behind....only total ppms. Does that make sense?

When I had deficiencies after I switched to bloom nutes my ppms would drop....fairly dramatically about 200 a day....that's when I was informed by my hydro guy that my plants were....ahem...."pigs" and to definitely up the nutes.
Weedhound Reviewed by Weedhound on . Nutrient Strength pH Balance Relationship? I just saw this on another site and since I hadn't heard this before, wanted to run it by some of you - whatcha think? "There are a couple factors that cause your PH to drift. The most common is running the nute solution too strong or too weak. If it's too strong, your PH drops. If it's too weak the PH rises. You have to find the balance point." Rating: 5