you def should check my grow. Too bad you cant follow the discussion I just had over the last week about this very thing. I ended up pruning, you'll have to make up your own mind.

The reason they are stretching is because you turned to 12/12 that happens anyway, right? But I'm also seeing stalks like I have on mine which arent natural and that's because most of your vegetation is competing for space. Look close and you will find lanky ass stems shooting all the way from the bottom right the fuck through the middle of your plant. Then they like spread out and cause lower down branches to have to do the same. Pretty soon your left with a ton of unhealthy vegetation. I would suggest you leave the tops alone but cut some of the lower stems and vegetation out. Do it when the lights are on and watch the way your light hits the canopy on the plant. All that growth lower down not getting light, is gonna need to growth long lanky stalks to compete for light. Chop it now so that your plant doesn't waste energy preparing to grow to a size you will never let it get too. Your doing a lot of that vegetation a favor anyway. Once it's starts to not get enough light the lower stuff begins to turn yellow or white if it's newer growth without light.

Lot's of people would say leave it, but after hearing from some pretty knowledgeable people on the subject I went ahead and pruned.

The real question is why it happened. Either too many plants, not enough light or a light leak causes stretching like that. I'm looking at the inside of the plant at all those long stems.

What's the over head light? Surely those T12's aren't the only light.