Rqs northern light auto, cheese auto

They are growing! The young plants seem to do wel. I gave them 25% of the led’s power. They are liking the light and multiplied by hight. Got the rqs-nutriënts for the first time and i’m using 1/2 of the recommended amount with ph’d 6.3/6.5 tap water starting on day 9 of the plants. 2 times a week rqs-solution and 1 time ph’d tap water 200ml per plant. The stems are very narrow and vulnerable so I gave them a wire to keep them straight up. Do you guys know what can help the stems get stronger? I have the oscillating fan blowing arround so the plants move. Any tips and triks are welcome. If you see any flaws let me know! Greetings