First two internodes are very long. The top one might be okay? If you recently increased light intensity, it might be fine, otherwise it is about to stretch like the first 2. More light if you haven't already done so. If you have, keep an eye on that top-most internode. Don't let it stretch like the previous two, but amp up incrementally and see how it reacts before doing more. take not of power and distance. Use that combo next time without the trial and error.