The holiday season got away from me a bit and prevented me from getting an update in on Monday but the plants are _really_ taking off. There are now visible bud sites and plenty of them.
*Full Disclosure*: I've significantly upgraded my light in my flower tent from a Spider Farmer SF-2000 to a Spider Farmer SF-4000 and, as such, I'll likely see my yield take off quite a bit this grow. It's certainly having an impact on the heat in the tent and, subsequently, the amount of time the in-line fan is running; that being said, the plants appear to be responding quite well!
The last two grows I've run have fallen off hard (complete and total yellowing/chlorosis and drying out regardless of consistent watering/light/nutes/pH) around week five of flower and, with that in mind, I'm trying to keep this grow as simple as possible. I'm purposely using no advanced grow techniques where I'd usually top, LST, and HST. The only "advanced" technique I'm using is a bit of defoliation but this is mainly just to avoid some of the dense bottom growth that tends to decrease air flow, increase humidity, and take away from more rewarding top-growth.
This week, along with replenishing nutrients, I've fully emptied out and cleaned my reservoir. While doing so, I noticed a fair amount of red-ish algae growth which I'll likely address with more consistent cleaning of the reservoir and some sort of additive (I'd welcome any suggestions and dosage if you've got any suggestions).
All in all, great progress.
Your best bet is to get beneficial organisms for roots. Someone mentioned hydroguard. I use this and have no algae issues. Having good organisms mean that bad organisms will be out-competed and won't be able to get a foothold.
Clean out your res very well again and start root bennies BEFORE algae sets in!