Yellowing on upper most tops, pistils browning early, 5th week of flower

I'm in my 5th of flower on an AK48. Having some yellowing on the upper most tops of the plants. Also the pistils are already starting to brown up some. Buds are still pretty tiny. I just gave a good feeding last night: - which is still slightly less than the BioBizz nute chart for week 5 of flower.
3L water
7Ml biogrow
8ml biobloom
3ml TopMax
6ml bioheaven
PH 6.4
Ppm 780
3g pot

Light is a 135w Apollo LED UFO. Temps range between 70-88 degrees. Had lots of fluctuating temps lately in my area. What do you guys think, am I ok here or what advice do you have? Thanks!

soil?

Diabolical666 said:

soil?

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Ah, I knew I forgot something. Biobizz light mix soil. Had lots of grows before using all the same. Primary difference with this one is the new 135w ufo when I started this one.

why you running ph low? should be around 6.5-7.0 before nutes added. Oh...you ran this ph before with no probs?

Diabolical666 said:

why you running ph low? should be around 6.5-7.0 before nutes added. Oh...you ran this ph before with no probs?

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The 6.4 was after nutes. Biobizz recommends starting with water ph'd to 6.8-7.2 then adding nutes. After nutes it's normally in the 6.4-6.7 range. I've done that for a while now. I have experienced yellowing in the past with other grows, one time due to a ph of 8 (my pen was off) and calmag def cause I was using distilled water. Now I make sure my ph pen is good and I've used tap water for my last few grows.

Bumpity bump bump...

WEll fuck bio bizz...jkjk Id bump the ph up to 7 then add the nutes. see if you somehow have some more nute availability

Diabolical666 said:

WEll fuck bio bizz...jkjk Id bump the ph up to 7 then add the nutes. see if you somehow have some more nute availability

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Alright thanks. Here is an updated pic. More brown pistils but the buds are still very small. Doesn't seem right at all.