White Lemon Hydrophonic

Hello So first with the battle of heat i would recommend changing the 24 hours light to either 20/4 or 18/6 it will cool things down and let the plants rest. You can consider an ac unit or cooler but that does take energy. Otherwise just keep the airflow up constantly, intake fan, exhaust fan and oscillating fans inside the space. You can look into using a silica supplement and kelp extract to help build the plants defense against these stresses too. If you can't cool the outer room down to bring in cool air, then just keep the exchange up, reduce the lights, and keep the roots cool...light colored pots, container with stones and a bit of cold water, water with cold water, just some way of making the plant think its colder than it is. Happy growing. ✌️

If you are really feeding all that nutes, it's no wonder they are like that, it's plain nute burn. You need en EC / PPM meter.

Much better. 250 ppm is a great level to be at this point.

Could just be a Cal/Mag problem with brown roots. I have grown plants in hydro that have not required calm/mag and there has been others that yellow up quite quickly without. But another sign of brown roots other than root rot is calmag. If it is root rot then good chance it has occurred due to your tempature problems. I choose to grow with Coco rather than dwc because i would struggle with my water temps.

Don't mistake height for progress. She's growing fine, maybe not the fastest on the planet, but definitely a healthy looking plant and growing good enough.