Co2 or just a shit plant?

i've recently posted that 1 of my roomates plants was browning at the tips. Then I posted that mine started this as well.. The weird thing is that each one of us has a really healthy plant and one that is a little bit behind that is browning. we both have almost the same setup and I was wondering if the bigger plants are using all the available co2 in the air since we dont have a co2 setup.

If they are from seed one is stronger than the other, if not then one has better access to the light.

You give so little information to accurately give an informed opinion. Is the browing at the top, or bottom of the plant would have been helpful for instance. If only at the top, I'd think too much heat frm your light, at the bottom, maybe nute burn. Either way, defenitely not the co2.

It is not a CO2 deficiency. Everytime you open your grow room door or breath around your plants introduces CO2.

yeah, the burn is on the bottom. Primarily on the first two smallest set of leaves. This might be nute burn like you guys were sayin cause we bought advanced nutrients and they burned. However I just thought it was a strange coincidence and that it might be related to something else rather than over feeding...primarily because I flushed his plant and it is still browning.

It's actually nute burn on the leaves. From when you pour the feed, it hits against the leaf then is left to cook beneath the light. When you do hit the leaves use a gentle cloth to rub the feed in. Plants love this, but you're only supposed to foliar feed during lights out. So I suppose it's best to try not to hit the leaves.

awsome info, thanks skunkushybrid! that sounds right. I'll try that.