First grow aka teach me

On day 13 they recieved higher nutriens EC 1 PH 6.4 Topped 4 plants on day 17 On day 17 I gave them another too hot nutrients solution EC 1.8 PH 6.5 can see some problems (in my opinion its nuts burn due not me realizing that soil was already a bit pre-fertilized + pushing everything too far due to its my first grow I found out at day 17, when I saw first signs - sadly I topped them that they and I brought them a lot more stress 😒 Transplanted plants into final 15l pots on day 20 Right now they are getting RO water only, will feed on day 22 again with EC of 0,9 I will aim for 6.2 PH as well EDIT: couple of people confirmed nutrients burn, so since I transfered 1l pots into 15l fresh lighmix, I will not feed until day 26 - they will get only hydro roots with RO water