help with 2 weeks old plants yellow tips and light green leaves

ppm 300 ph around 6 i flood 4 times a day around a minute every time im using grow tec ionic plants are about 4 inches tall the trailing leaves are yellow next set of leaves up have yellow tips and working there way along the leaves lights are about 2and half to 3 ft away from the plant but they look very light green aswell sorry no pictures thanks do i go by 500 factor ppms or the 700 factor ppms metre is Bluelab EC Truncheon

How hot is it in the room?
Yellowing could be caused by:
Too much light
Too hot
Too much nutrient.... Or insufficient nutrient
Too high or low of PH.
Poor ventilation

Try making a new batch of nutrient and getting the ph closer to 5.5 and TDS around 350. Make sure the temps of the water is around 68-72 and the temps for the room are around 76-80 degrees.

If you don't have a fresh supply of air coming and going out of the room every minute, this could cause you leaves to yellow also.

ppm should be 500-600 for seedlings, increasing to 900 during flowering.

330 is way too low - not enough nutes for plant.

pH is ok, try to drop to 5.5 if poss.

room gets up to about 85 90 light cycle is 7am till 11pm ph is 6 air vent at bottom around 6 inches not running the intake fan outlet is about 24 inch gap right up the top of the ceiling sixe of room 4ft l 3ft w 7ft h lights are 250 ive just made a new solution ppm300 ph6 should i flood 4 times a day could you advise me on this thanks

85-90 is too hot, try cooling it a bit. I would flood 1-2 times a day.

cheers guys