Im new here but not new to growing
Currently growing my 4th gen top44xhaze heaven & papayaxhaze heaven and got some white ice.

The problem i have is about 3 weeks into flower, the stems will lose all their colour, go very wood like and stiff.
This is followed in week 5 of flower by the leaves having a very dry feel to them and grow thinner, not seeming as healthy but there are no nutrient deficiency or tixicity signs.(By thinner I mean when u pinch the leaf, not thinner leaf fingers)

The end product never seems effected by this, but having visited a few other grow rooms i know my plants arent how they should be in the flowering period.

Any advice on what could be causing this or could treat this would be greatly appreciated.

The roots arent potbound in the grow
I grow hydroponicly in clay pebbles, drip feed, well oxygenated nutrient solution thats flushed out regularly.
Temps usualy maintained at 27.5C, Solution temps 23C, Humidity during flowers at 55% for first 4 weeks and 45% for the last part. The plants are fed for 45 minutes 5 times per 12hours on and aren't overwatered, the oxygen seems to be in good supply in the solution.I have also ruled out silicone deficiancy.

A picture tells a thousand words.....Get a picture up buddy Im sure one of us will be able to help you out

Thanks
The current ones ive got are 6 days into 12/12 and are still ok for the moment,
The best way i can describe it, is the stems look like stems off a chopped and dried plant, but when theyre about week 3, no green to them and become almost brittle, while the buds will grow normally.
Ill look through some pics from previous grows for an example when im back from my friends.

you growing in a tent or room?

1.5x2 metre x 2 metres high home made room.
Sealed, 2 100rvk's in and a 320 out, temp and humidity never seem to be a problem

hmmm - how queer!

are you using Ozone?

No just CF's on the extracter, theres no dehumidifyer or air conditioner unit in the room either, and ive got a 18 inch oscilating fan to keep the air circulating

then it's got to be genetics or nutes???

i've been growing for nearly 15 years and i've never come across it before but hopefully someone else has!

no lino in the room or mdf which isn't sealed is there?

Smokeandmirrors i was thinking it was a nutrient deficiancy of some kind, looking up i found silicone helps cell structure but it had no effect when i increased the amount in a previous grow and ive kept using it since.
Genetics i would also rule out too, as its happend with all strains ive grown previously.

I use the medium feed advanced nutrient guide when feeding, but i do add 20% more Sweet Leaf than it suggests

Groovelick
Not that im aware of, the rooms plywood, lined with damp proof membrane and thats covering in mylar. It was constructed about 3 years ago and doesnt seem to leek anywhere apart from a small gap around the sliding door which is very minimal, light only just breaks through.

(link to external site removed )
This pics from a high def vid taken 4 weeks after lights wer gradually reduced to 12/12, bit out of focus but you can see how lifeless the stems look

ah sorry