I would not suggest waiting until the third node to feed in this system.
Growth is too explosive. They will need nutrients sooner.
Though nute load and ideal PH are both strain specific, I'd suggest at this stage to add to 0ppm RO water - about 200ppm of Cal Mag and 100ppm of high nitrogen "grow" fertilizer. Keep the Cal Mag there, and up the grow fertilizer maybe 50ppm a week for a few weeks and see how they do. You may need to up it more quickly if they show any deficiencies.
Allow your PH to fluctuate between 5.0 and 6.0, but do not let it stay below 5.8 for very long during veg. The plants won't be able to take up the Cal-Mag if you keep it too low, and when they grow that fast, they use it ferociously. Try to stabilize at around 5.8-6.0 and let it drift down for a couple days, but then get it back up to 5.8.
Once your plants are flowering and you notice they've stopped growing big fan leaves, then steady closer around 5.5.
I've been working on my germination technique as I've had some problems in this area.
So far, the only method that has gotten me good success is this:
Cut off a very small piece of capillary mat (this is a white felt-like sheet of fabric used for wick systems) about 1" sq.
Dip this in a 200ppm solution of RO, Cal Mag and Superthrive (or equivalent vit B supplement).
Fold in half, insert seed and slide into baggy.
Squeeze out excess water (keep damp) and loosely wrap up bag.
Put this onto a heat mat and cover it with an opaque bowl or equivalent.
This will stay 90`-95' F.
Check every 12 hours, open bag to allow fresh air in, and if necessary, add water solution to keep damp.
Most seeds pop at 24 hrs.
The radical (little root) will grow into the capillary mat. This is fine. I cut off most of the excess mat and plant the whole thing in either rockwool(for hydro) or seed starting soil.
I've had much better experience using the capillary mat than papertowels. It holds the perfect amount of air and water when you squeeze it out. You can find it online, worthy investment IMO.
The temperature is also very important, as is complete darkness.
I hope you get your germination technique sorted out. I destroyed a lot of expensive seeds until I adopted this tek.
