HELP! Is this yellowing normal for flowering

[NotAFarmer]

This little girl is in her 4th week of flowering and I've been seeing some of the lower leaves turn yellow some even falling off. I'm getting mixed messages about whether this is normal, but I'm leaning toward no.

A bit about my grow:
~70/30 coco/perlite in about a 5 gallon bucket
DynaGro bloom at roughly half strength every watering
Water about twice a week when the coco starts to feel less wet
Water + nutes PH'ed to 6.0 going in. Tested coming out this morning around 6.4
Water is technically distilled water as I reuse the water from my dehumidifier
Watering until there's about 20% runoff every time, runoff water is disposed of
Temps kept around 68-74 degrees round the clock (this has been adjusted up recently as I was noticing some purpling on leaves)
Humidity kept around 50%
There is a small fan blowing directly at the base of the plant on a light breeze (barely moving some of the leaves)
Plant is White Widow from Growers Choice

I had some trouble early on (during veg) with fungus gnats which I corrected with a mixture of yellow sticky pads, a fan, and spinosad. I see one or two occassionally but much less frequently lately. As far as I can tell reading on this site, this still looks like watering issues or perhaps PH issues. The water coming out is a little on the high side of acceptable for coco, so maybe I just need to lower the PH going in by 0.4 until it's corrected coming out? What do you guys think?

Thanks for your help


Edit: I wasn't completely right about "roughly half strength" nutes. I'm using about 3.5ml / gal per watering; which is slightly higher than 1/2 strength (roughly 2.5ml / gal)

[homegrown]

I think your problem started from your watering practice. I started out using those pots but had another hundred holes drilled in them. If you have been watering twice a week their not drying out enough between waters. I water approx every 4 days in 5 gal fiber pots and that's ONLY if their light to pick up. Another reason i think too much water is fungus gnats, they love wet soil and reproduce in it. I haven't had a fungus gnat problem since switching to coco 3 years ago. Your pH isn't horrible but i would have my pH out at around 6.2 and to bring that down your going to have to water in at around pH 5.8-5.9 for at least 1 watering. You wont see much of a change in pH dropping by 0.4. On to your nutes, Dyna-gro Bloom 3-12-6 is actually pretty low in nitrogen so if you are cutting your nutrients in half she's only getting 1.5 parts N per gallon. And lastly..are you using cal-mag for every water? So..in a nutshell, too wet, causing root issues,causing nutrient lock-out.

[Gingerbeard]

Hey NotAFarmer I'm editing this for the info I gave. Dyna-gro is 1tsp, 5ml, per watering. You are correct in saying 2.5ml is 1/2 dose of nutes. I use full strengh, 1tsp, ever watering.
I'm real sorry about that. I read one thing but understood another.

[NotAFarmer]

Bah alright, that's all good info.

I got ~5ml / gal by looking at the instructions that say for hydroponic non-recirculating systems use 1tsp per gallon. A quick google lead me to believe 1tsp was roughly 5ml; cut that in half and got 2.5ml / gallon. Can you link the Nebula Haze review, please? I'd like to have a read.

And, no I wasn't using cal-mag. I was trying to read between the lines of several articles on here about this particular nutrient system and came to the incorrect conclusion that DynaGro grow/bloom were all I needed for veg/flower. I see now reading a more coco specific article that I need cal-mag as well. It's been ordered and I'll start adding it when it comes in.

Good to know about the watering habits; I'll cut back by a day or two and give the pot a good weigh before watering next. I couldn't decide if I was doing it too often or not enough; this is my first grow so honestly I was happy to make it this far.

Thank you both for your invaluable insights.

[Rwise]

I'll say I dont use coco, but did you prep it? I have read that one must prep it with calmag, or maybe it was pre-preped, IDK.

[NotAFarmer]

I did not know that was a thing. I basically just re-hydrated the coco brick with tap water, then mixed in my perlite and planted the seed. I've got some calmag on order should be here in a couple days, I'll start adding that to the water each time at the recommended dose and hope that helps some. Lesson learned, should make the next grow go that much smoother.

[Rwise]

Epsom salts work just as well.

[NotAFarmer]

I'll keep that in mind as well; thanks for the tip!