what can it be?? little watering? excess fertilization?

but isn't the dose too much? I don't go into excess of fertilizers ??

more nutes: 3ml grow 3ml bioheaven 2ml bloom 2ml Algamix 1ml Topmax Peace man!

I would change the distance of the lamp to 50 cm, slow down topmax to 1 ml and add 2 ml grow. and watch... Peace!

Be careful on this stage they dont need a lot of nitrogen. Looks like they have some sort of excess. Good luck!

I see a few burnt tips which indicates a excess of nutrients, also eliminating the grow was not a great move. I normally find in bio bizz you need the grow and the bloom all the way through the growth cycle. 1.8 EC is not a true indication of the nutrients available to the plant as you are using a organic fertiliser which will not register on the EC meter. I would just go back to 1ml per L grow and 2ml per L bloom until they start to look happier. You could also flush and then go back to the 1ml grow 2ml bloom. I did also wonder if the yellowing tops were somewhat light related but the gap seems good to me. Hope this help buddy👍

Thanks @Roberts for your answer, I will take note of what you told me, if I'm not mistaken you already told me in the past few weeks about the run off 20%.😉 I will do it for sure so I can really understand the pH of the soil