It's not the lights you're using, mine are worse. It very well may be the AMMOUNT of them though, partly ... that poor thing is light starved. Look at how much it's stretching!!! My own plant has about as many leaves and nodes, but with about three inches of very bushy height. I also have seven of those lights over it for 18/6. It's very inexpensive and it works. I'd say don't do any pruning. If you need to move something out of the light path, use twine and hold it off to the side that way. LST that thing.