Athosanswered grow question 6 years ago Actually what you are seeing is quite common: it's nute burn. You mention you are using fertilized quality soil, that means that the soil already has a lot of nutrients in it and on top of that you added more nutes. Alg-a-mic won't burn the plants since it barely rises the EC/PPM of any solution, but Biogrow can be quite strong n young plants.
I use Biobizz too so I know quite well the concentration of the product you are using. 2 ml/lt of Biogrow has a concentration of 0.6EC (300 PPM) and assuming you are using regular tap water, that usually has a salt concentration of 0.4EC (200 PPM), that means that you are most probably feeding at a strength of 1 EC (500 PPM). I've had young plants burn at less than half that strength when they are in pre fertilized soil.
11 liter of fertilized soil, lasts me 8 weeks without needing nutes, and you are using a 20 liter pot, you should not need any nutes for the whole grow, or maybe a tiny wee bit at the peak of flower, but not at this stage.
Do a flush and stop any feeding. Also sometimes too high pH of water can lead to weird leaves symptoms like them curling upwards like a taco, it has happened to me too; there could be some of that too.