Indoor tent grow with possible light burn issues or going to heavy on nutes?

[AndyECV]

3 Clones (3 different strains Mendo Breath, DeathstarxCherryAk, and Cookies. I am at almost 3 weeks since planted. Last Friday I switched from 600w HPS to 1000w (250 actual) full spectrum lighting. Was getting severe light burns (I think) but explosive growth before the switch. With the HPS I was also getting the heat factor and this set up in my garage had the plants at a comfortable 75-80 range. At night the plants are getting down to 55.... and High of 72 with humidity 60-62 range consistantly. I run the lights 24/7.

So couple of questions.. should I introduce a space heater to keep temps closer to the 70-80 range? or the few hours over night that it gets cold.. will that not impact growth?
Could the yellowing leaves with dark brown spots be caused by overfeeding? (I use all veg components of the General Organics go box and tap water (perfect PH)

Thank you,

Andy "greener than my leaves"

 

[Green75]

Can I see a picture...yellow with brown sounds like bad ph...

 

[Karlee]

Hi Andy

Light burn is serious use the hand method, why did you switch the light if it was growing so well? You want the best root system you can make and explosive growth is good for that!

 

[Nartak]

55 is low but cold leaves will not get those colors!I really will just point to what green said..Either that or lightburn if not root problems..But lets take the usual suspects in first..Ph and Light!