mh light durring flowering and hps

hello everyone, first time grower in the 7th week of a hydro grow I have 8 plants and i wont to start flowering. I am running one 400w mh and one 600w hps hung side by side should I flower with the hps solo are with both. How will it affect the plants production of buds and the growth.I am at 26" and only have 2 more feet left for plant growth does anyone have an idea if I will make it, thanks this a site.

Probably both. You'll be glad you did.

You can use both but you better start flowering ASAP. They are going to double in size during the first few weeks. Be prepared to tie the back.