You said;

"My pH is constant around 5.8."

Odd, Because that sure looks like high PH lockout to me.
Can I assume that you monitor the tank PH constantly/daily?

The trouble began when you increased the ppm.
That sounds like a clue!

That usually causes the PH to drop more than before.

Good Hydro nutes are formulated to drop tap water from 7 and above to around 5.8 or so.
If you start with 5.8, then mix in the nutes, you get a drop that you don't need and you end up having to add PH-up.

The air-stones also play a role here.
Dissolved CO2 lowers PH. Dissolved Oxygen raises it.
I looked up the Technaflora and it has plenty of cal/mag.
'course that makes no difference if the PH is off.
Plants won't be able to use it.

Disclaimer:
I'm really not an expert. This is just my best guess.
There are folks on here that I admire and respect for their troubleshooting skills.

Now, they have all the information they need and should be around soon to weigh-in.

Do have one more suggestion though;
Next lights-out, be standing by with white light and/or a flash and retake those pics.
Be sure to show some of the growing tips in your photo.
They are your best indication of what is actually happening.
If the plant is raiding it's fan leaves for mobile elements to support the new growth, there will be signs in the new growth.
Grow-masters can read them.
I'm still learning.

So I'll haunt your thread until an answer is found and be dat much smarter for it, yah?

By asking a clear question you have done all of us a service when a solution is found.
So, Mahalo nui! =Thank you muchly

And, of course,
Aloha. -- Alo = to give, HA = the breath of life

Weeze