Well like i say, initally the yellowing on the older leaves was the problem i was having so i added the urine mix to counteract it. That was saturday morning; I looked at the plants today (monday- 6:00) and noticed some of the middle leaves are browning on the tips but is seems like the yellowing stopped since it hasnt got up the leaves any further than it was on saturday. What did u mean by heat on the canopy? I have my lights on set like 3 inches above the plants. And as far as browning and yellowing on the newer growth goes, ther eis no yellowing. The is no browning on the top 2 nodes but there is some browning on the tips of the 3rd node down from the top.