Any tips please !

The paling is a N-tox.. and the damage beyong paling is advanced progression of it. I can tell by your description of watering that you have developed bad habits. You do not choose how much water to give. Stop doing that. you give enough to accomplish the task effectively. 1) Water entire pot - never leaving a dry pocket. You cannot hurt a plant fully saturating the substrate. If it happens, it's because the substrate is poorly constituted. Add more perlite if you get droop after a normal irrigation. 2) wait for top 1/2-1" to dry and repeat. (with coco coir, it holds less water per volume and you do it a bit sooner relative to depth of dryness) - never allow wilt to occur, of course. It's that easy. If you re-irrigate at similar point, it'll take the same volume of water. This is how much water you need and can plan around it, retroactively. So, the droop could be due to your watering habits. Clear those up first, then re-assess. Referencing mulder's chart, looks like N does the locking out of other stuff and not the other way around, so after a couple proper irrigation cycles, if still having an issue, i'd up the N but maybe scale back on other parts of fertilizer mix, too. if the issue progresses quickly in meantime, that's a reason to change the formula now rather than later... if you can afford to, better to do 1 thing at a time and see how it impacts before moving on to next step. Sometimes reality doesn't let us be patient, just don't assume that's the case. The plants look a bit too lush, expecially for pictures taken under a grow light (has a paling effect compared to eyeballing them in person under normal lights). Usually this would be N-tox, but you clearly have a n deficiency symptom creeping up from teh bottom. N-def is one of the easiest to diagnose from leaf symptoms, fyi. As far as percentage of perlite or similar -- 50% for soils / sphagnum peat moss mixes. 33% for coco coir. With this ratio and proper irrigation habits above, it is impossible to overwater or drown roots. you'd have to run many gallons of water through the substrate for 15-30minutes to cause droop, lol - so under these conditions when you see droop you know immediately that it is not because of irrigation. If you have ~1/3rd, that's probably not going to cause problems, but is less than optimal for the root zone. No big deal, just add a bit more next time, if so. If potting up, could add extra to that, but if in final pots, just tough it out.

It's called "Epinastie" (German). Your plants do that because they produce too much "Ethylen". This is caused by a lack of oxygen in the root zone. Usually because the earth is too wet