Lots of great info here. /s
Start clones in 300ppm actual nutes. RO water is best to use in DWC or most hydro rigs. Use a syringe or turkey baster to suck up some nutes and top-feed a couple times/day until roots hit the nutes which should be about 1" below the bottom of the net pots.
I've done 50 or so DWC grows since 2001 and my RH is often as low as 15 - 20% and the plants grow fine. At low RH they will go thru a lot more water andsuck up more nutes than they can process so that can lead to toxic salts buildup that shows up in mid-flower so if the RH is low so should be your ppm. I'd run at 500ppm .5 Hanna scale when it stayed low. Lucas is fine after the stretch but use them all until then. If it was a summer time run and the RH was up to 50 or over then I'd go up to 1200 for the stretch depending on strain. Can take 2 or 3 runs of the same strain from clone to dial it in good so with new ones it's best to stay lower until you see some bottom leaves yellowing then bump up the ppm in stages.
If you can keep your RH up then that's best and one of the reasons I'd like to go with a sealed grow room but need to drop a couple more grand to do that right. Expensive f'n hobby when you aren't selling your product.
For many of my grows I would never change out the nutes once but would try to do it after the stretch to switch to full Lucas style. Don't go by any set numbers for Lucas but just use a 0-1-2 ratio for most 3-part nutes. The AN nutes with the Gorilla on the jugs is not the same formula as GH 3-part or even AN's Jungle juice which uses the same mix. I wrote out a description of the difference just a few days ago when I finally noticed after four or five years.
I've been using AN 3-part for 20 years. I bought gal jugs about 5 years ago and just now noticed that the N-P-K ratios have changed but I've been using it just like the older stuff that has the same ratios as the Jungle Juice and the GH 3-part. This may explain some of the problems I've seen in flowering especially when I switch to Lucas Formula feeding after the stretch. I have 1L bottles of the older pre-pH Perfect 3-part and dug them out to check.
Old AN, JJ and GH are Grow - 2-1-6, Micro - 5-0-1, Bloom - 2-5-4
This 5 yo AN 3-part is Grow - 1-0-4, Micro - 2-0-0, Bloom - 1-3-4 (Has the Gorilla on the jugs)
Totally throws thing off to what I had become so accustomed to. I'm going to have to sit down and reformulate some of my mixes to be feeding each nute at the same ratios I was before. Much more diluted now too. With less than half the N as before it throws the Lucas feeding way off. No wonder the old leaves yellow out so fast and early.
I also have some REMO nutes from winning a 7 - 250ml bottle kit in a raffle at a hydro store I deal with and their ratios are different again.
G - 2-3-5
M - 3-0-1
B - 1-4-7
Flip a coin I guess or dust off the math books and nail it down.
Just add some nutes to that water and leave it in. 1ml/L of each of the 3-parts is enough for now. Drop the Super Thrive and Rapid rooter. Check to see if there are any exposed holes in the net pots near the top of the hydroton balls. I'd top the pots up with balls just to make sure there's no light leaking into the rez. Can use them more than once so they won't go to waste.
Those plants can recover and grow just fine.
Good luck!
