Wkarma's Grow

I did the dry ice experiment today first i put 2 lbs in a container with no lid, it all melted in about 6 hours. Then i put 2 lbs in a cooler i found a clear hose that fit perfect on the coolers drain plug closed the cooler and let the gas out of the drain plug hose. The cooler dry ice took about 24 hours to melt. I also see bubbles forming on the bucket system i set up so this should also be producing co2. I have 6 plants in a circle with the cooler hose and the bucket both coming up in the center of the plants.
Peace

I got up this morning to check my plants 5 out of the 6 were green and growing and looked very healthy. But the sixth ones two spike leaves had turned brown and shriveled and looked dry. I am not over watering because they all get the same and the other 5 look fine. What happens if to much co2? This came on really fast (overnight) I havent used any nutes yet.
Can Anybody help?
Peace

Pictures? VV

Ok 14 days into the grow. The sick plant recovered on its own and all 6 mazar are doing fine, only about 4 inches tall but getting thick with leaves. Im putting a 2lb block of dry ice in the room every 2 days and have the yeast,toast and sugar water co2 bucket system going full time im not sure how much co2 the bucket is putting out but my babies are loving it. Im going to start them on nutes in a couple of days 1/4 strength. My ph is a perfect 6.5 and i am able to keep the temps at 80 with the 1000wt hps on and about 73 when its off. Im going to try and add some pics soon.
peace