Flowering = Yellow leaves?

I know this as been asked many times before but I need confirmation from some of the experts.
I have been flowering for a little over 5 weeks now. For the past few days, I noticed that some of the larger leaves at the bottom of the plant are turning yellow; almost seems like they are "wilting" and end up falling off.

From my research it seems to be a normal thing. The plant seems to be healthy, besides those leaves about 4 so far, the rest of the plant is a nice deep green, bud are growing (slowly but growing)

So can anyone confirm that it is normal or should I be on the lookout for upcoming problems.

Using an HPS 250
Ph is at 5.6
Only 1 plant (unknow bag seed, I know Cheetah it's awfull , Sativa dominant for sure)

As always thanks for your time

I just took a total of about 10 leaves off of 5 plants that are about 6 weeks into flowering. In my experience this is common. I have had this happen every time and the plants are otherwise very healthy. Not to worry. If the yellowing presents higher up the plant or near the buds you need to look for a problem.

Just the confirmation I needed. Thanks for puting my mind at ease.

Usually at this point in flowering they can use a little extra nitrogen also..