I think you need a certain amount of post to be allowed to post pictures. It might be 50 or something.. Maybe 20...

You need to give me the height of the plants and the node spacing. 6 leaves as in 3 nodes ? Not sure what you are speaking about. If they are very tall with 3 nodes the light is too far away and making them stretch towards the light. This gives thin stems. If you bend the stems yourself once a day that will help strengthen them too. But dont break them !

With the HPS watch what the plants are telling you. If the nodes are too tight the light is too close, if they are over an inch then move the light closer.

Take care