I have found that they can be ramped up pretty fast.. I am such a pussy when it comes to this, so I tend to go up slower than I should, and end up having to pick my nuts up off the floor and feed them a little more aggressively than I do, cause their roots tend to grow pretty quickly. I start them out at about 150 - 200 ppm and it only take a week to 10 days before your at 350 - 400 (keep in mind I am using .5 conv, so at .7 the ppms are even higher).. Since I water daily at first in order to get the roots into the res, one day my ppms will be 150, then the next 170, then 200 and so on (if I choose). This is also another reason hempy is nice, you can just play around with your PPMs without having to continually dump and refill a big reservoir, and since you CAN water daily, you can play around daily if you want. 5.8 - 6.2 is your PH Sweet spot in Hempy's.. My suggestion is to get a decent PH and PPM Meter.. When I started Hydro, I went out and purchased a Pricey HANNA tri meter, and I just hated it.. Takes forever to get to where it needs to go, constantly needed calibration and would seem to fluctuate alot. I recently purchased an Oakton Eco Testr PH 2 meter (somewhat inexpensive), and as far as I can tell, its giving me an accurate reading, its giving it to me QUICKLY, and most importantly, NOT Giving me any SHIT. So I went ahead and Purchased its brother TDS Meter, which pretty much does all it needs to, and does it quickly,, No fuss, no muss. Check em out if your in the market,, and USE the PH Storage Solution to store the meter, not the Calibration Solution. This is a tip that I recently learned, and I cant say anything bad about it.