Thanks for replying Highseekerz. That clears a few things up for me.

Another question, if anyone can answer.....

I am currently using a 250W MH and my plants have just come into the veg stage. I want to change to 600W HPS as this will give the plants more light and I know HPS is pretty good for both veg and flowering.

Will the change from MH to HPS so early in the veg stage bother the plants? Or will they take to it easily?

I've tried to take pics of my growroom to post in this thread but the pics come out fuzzy 'cos it's too bright in there. If I get any good pics, I'll post them.

Cheers