what your looking for is the ec/ppm & ph to stay the same as the water level drops, that way you know that they are drinking the water & nutes at the same time,
if they only drink the water the ec/ppm will go up, so add back only water to get that ec/ppm down bellow the original strength,, i.e. if you had a ppm level of 1000 and they drink the water and not the nutes say your ppms go up to 1150, i would get my ppm's down to 800 on the next top up & the opposite if your ppm's are getting lower.
hth middy
Sound as mate!!!...So if im noticing a rise in numbers (ppm) then I need to counter balance this by adding more water?, then if its going the other way my solution is getting weaker and my babies are getting hungry??...My current dwc is a single pot and I never checked the ppm or anything and just winged it and did a reservoir change every week adding fresh nutes. Its gone alright and is currently just 2-3 weeks in 12/12. But with the DWC im monitoring the ec/ppm is a 4 pot and a much larger reservoir (50ltr) and I dont really want to be adding a fresh reservoir with fresh nutes if its not needed. Now sorry be a pain but after 5 days the ppm has rose by 0.04, so on the basis as whats mentioned above then they are feeding on more or less equal amounts of water and nutes, maybe just a little more water. I am noticing some nice new growth in 2/4, but those 2 did have better root structures, but there doesnt seem to be any deficiencies in the smaller 2.
Keep in mind, unless your using a reverse osmosis system, your water will NOT have a base line of 0 ppm before adding your nutes, most tap waters sources test at around 150-400ppm just by itself. Also, most nutrient companies will list what the target ppm should be based on plant age (ie. http://generalhydrop...-REC-Charts.pdf - General hydroponic's feeding guide; the ppm suggestions are right under the week numbers.)
I am sure im not using a reverse osmosis system, mainly because I dont know what 1 is lol, and also before I added my nutes the water, which is your usual bog standard nasty ass tapwater was giving me 200ppm.
I had a look at the feeding schedule that you linked and its for a different brand, does this matter???.. I have been following this (
Ionic Hydro Grow Schedule) the only time I have swayed differently was for the lower concentration when my 'mother plant' was a baby which I started on 1/4 strength and them added more weekly, this is what I was planning on doing on these 4 clones. But like I mentioned above I dont really want to be wasting nutes this time because im using higher volumes.