5 weeks flower 400w hps

Some more pics of my first grow, no idea of strain sorry. Alot of leaves are turning yellow and falling off, I believe this is normal because the plants look so healthy and from what Ive read on this site, am I right?
Any guess on how long to go? Or when to stop nutrients?
Thanks heaps

looks like you got a few weeks to go. So keep the nutes comin for now. They look nice man. How many plants u got in there.

Cheers mate. I have two plants in a space of about W600 x D300 x H1600mm.