Looking for help identifying the problem with my plants.

[MoonDog]

My plants are 2 1/2 months into veg. They have been doing very well. All of a sudden the new growth starting coming in yellow and some of the bigger fan leaves started getting brown spots. I added some calmag to my nutrient solution to see if that might be the problem. They are in 2 gallon cloth pots, I feed them once a week with the Cornucopia line of nutrients and water them with just distilled water with calmag pH'd down to 6-6.5. Oh they are also in Fox Farm Ocean Forest Soil. My temp hovers around 70-80 and humidity is 50%. I think I know what the problem is but Im not sure. I recently for the last few weeks started giving them 24 hours of light instead of the 16/8 they had been on. Im thinking light burn. Can someone please confirm this? I was told the plants could get 24 hours of light if you wanted. Any advice would be great.

 

[Dice]

Sounds like you got everything dialed in & also what the problem is. Id raise your lights a little or go back to 18 6 & see if that helps.

 

[Canuck147]

If they are autoflowers, you can have the lights on 24/7.
You cannot add pH up or down to distilled water. Doing that will make the water extremely acidic or extremely alkalinity.