Nutrient Problem ?? !! Help !

Hello guys , i'm having a problem with 2 plants , some help would be apreciated ! thank you !
In the first picture its very visible the problem ! In the second picutre its a diferent plant , its not so visible but u can see the leafs are slightly turning yellow in the "middle"

fix my pic's ? hum ? why ? i'm seeing them ok , whats the problem ?

Maybe a calmag problem. What ru feeding them what's the ph of water, soil and run off? Have you checked for bugs with a loop or scope?

What he means is cut off the lights when taking pics. It helps to get a more natural color of the plant so that it can be more easily seen. U look like u are still in veg. So what are u giving them and how much? And what is the PH of ur water and ur run off water?

thank you guys for the advice's but i've been searching arround and i found a correct match to the problem ! Its Light\Heat Burn !
But anyway ! i Have my ph of water controled ! im feeding them with the Hesi Line Products ! Half Dosage ! Since im Using BioBizz Light Mix Soil , im feeding them every eatch other watering ! so im feeding them every 4 days . because i water them every 2 days with 300ml! Im using a 400W Hps Philips Green Power bulb ! But maybe it was to close to them , i already put it further away , so i will be on watch now ! to see if its ok now! Any way , my plants are about 1 month since i put them to germinate ! How do you guys with more experience think they are doing ?

PS : Its my first grow ! thank you !