I think my plant has stunted growth.

I was using some root nutrient shit and I just found out the pH in my water was 8.2 something...yeah, yeah well it has been under 24 hour lighting and I recently just started using tap water. The stems are turning red and I already cut the bottom two single leaves off. Today I started using 18/6 lighting. I dont klnow what im doing so cunfused, but im still going to let it grow.

keep it calm and give them some time and properly PH'ed water/nutes. You might flush with PH water/nutes and give them some time to snap out of the shock before resuming with regular feeding at the correct PH, probably a week before you see vigorous growth and a steady water uptake again. Its always good to focus on dialing in your climate, reducing any swings in humidity and temps, making sure your environment is stabilized because this will reduce risks of shock and your plants will better tolerate and adjust to potential stressors.