WTF am I Doing wrong this time?! I have checked every self diagnose, still stumped

What's happening everybody,
Sooo... I can not understand why this specific cultivar has been giving me so many problems, whereas my first two runs went well. Second bbetter than first obviously. So here I have 2 regular seeds of fire fruit snax from therealorangetreecreators2. Which is (TK x wifi) x (fruity pebble og f2 x orange tree F2) I'm very excited but from the start I've had problems. I'll explain.. I have been using Ffof (never has been too "hot" for me) anyway I'm using a Mars Hydro 300w for veg for the plant pictured second. And a qb120 from hlg.. They are right around 5 weeks from the time It first broke soil. I had them in red solo cups for the first 3 weeks or so and they were looking great w just water and towards week 3 after they were at probably the first set of 7 finger leaves, the bottom leaves started to get yellow and a little burnt looking. However all new growth looked good. So the past ycchcouple weeks I've spent hours readin "self diagnose" plant problems. So I raised my lights from 18' to 26' on the Mars Hydro and from 16' to 24' on the qb120.. But doesn't too much light problems start from the top down as opposed to me losing first three or 4 sets of leaves after the cotyledons.. I have had them on a 18/6 from the start on a timer. However, besides my clip on fans and my standard fans to keep air moving etc I have very little ventilation. So also 2weeks ago I started keeping their door to the tent open so it's been a steady 72-76. So now I'm at bout 4 1/2 weeks and they both have about 4-5 good sets of leaves. Does anyone have any Idea what's going on or why I lost these leaves. I want to know what I did so I won't cause this again..
Even if it is doing better . Take care everyone and any and all constructive criticism and help is welcome!! Like immediately. Lol

Nobody?

SirDirkDiggler420 said:

Nobody?

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Talk about pH and newts

SirDirk,
Sometimes shit happens and we're never able to track it down. I lost some leaves from a plant I had fed...and realized that I forgot to stir it up after adding ph down.
JD

Yeah, what have you been feeding them? And like BW said, are ya checking PH? I don't think it's light issues, if anything you have them too far away. I use a Mars 480 to veg with, always keep it around 12 to 14" with no problems. You are right, if they were getting too much, it'd show at the tops.
And how much and often are you watering?

You have the N toxicity claw tips. I get that with FFOF. Check your run off and see what the ppms are. I was rather shocked to learn that my run off ppms with FFOF and no added Nutes was 800+ ppm’s. Def don’t add any nutes to FFOF until you hit flower or until they start showing they need food.

Here's some of my experience FFOF, and FFHF....(its pretty much all I use)
Also I agree with the above post from jtrizzy 100%.....

Right out of the bag, on multiple occasions, I tested the PH with my Bluelab PH probe (Leap probe) and I have seen readings as low as 5.5 after a mild wetdown…..with 7.5 or higher tap water.....These results have been duplicated by another Bluelab Leap owner, several times...Runoff PH readings had me chasing my tail coming out 6.5+, cycle after cycle, until I got that Soil probe, and confirmed our suspicions. Whatever buffering these mixed have, or HAD, don't cut it for my usage...
FFOF claims to be PH of 6-6.5..... Its not. At least the dozens of batches, in my area, over the course of many, many months....
I now amend garden lime, or dolomite lime in the pre-use stage to get this corrected.....

Chip Green said:

Here's some of my experience FFOF, and FFHF....(its pretty much all I use)
Also I agree with the above post from jtrizzy 100%.....

Right out of the bag, on multiple occasions, I tested the PH with my Bluelab PH probe (Leap probe) and I have seen readings as low as 5.5 after a mild wetdown…..with 7.5 or higher tap water.....These results have been duplicated by another Bluelab Leap owner, several times...Runoff PH readings had me chasing my tail coming out 6.5+, cycle after cycle, until I got that Soil probe, and confirmed our suspicions. Whatever buffering these mixed have, or HAD, don't cut it for my usage...
FFOF claims to be PH of 6-6.5..... Its not. At least the dozens of batches, in my area, over the course of many, many months....
I now amend garden lime, or dolomite lime in the pre-use stage to get this corrected.....

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Curious have you ever tested that run off ppms? I was shocked by the ppms it produced.

jtrizzy said:

Curious have you ever tested that run off ppms? I was shocked by the ppms it produced.

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Oh yeah, many times....just like you 800+, and that's just the stuff that's soluble at the time!!!!
I also add 40%+ coarse perlite to the bags before use.

Chip Green said:

Oh yeah, many times....just like you 800+, and that's just the stuff that's soluble at the time!!!!
I also add 40%+ coarse perlite to the bags before use.

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Ya I just added 40% perlite with this grow currently. Seems to be better.

Opie1971 said:

Yeah, what have you been feeding them? And like BW said, are ya checking PH? I don't think it's light issues, if anything you have them too far away. I use a Mars 480 to veg with, always keep it around 12 to 14" with no problems. You are right, if they were getting too much, it'd show at the tops.
And how much and often are you watering?

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Hey thanks a lot for reaching out w some help. As you and and a cpl others said, I'm confident it's ph and somewhat a nute problem. On my last run I used my tap water which after a day or two of sitting room temp would be right in the 6.6 range. Well this time I "cleverly"filled up a bunch of bottles so I didn't have to do it as often. Well I check one of the longer sitting bottle which was going in 5.7 ish. I haven't checked run off as I have not watered them since. I water usually every 4-5 days right now in 3 QT pots. Or when soil is dry n lightish.. Also like jtrizzy said, I have the mean N claw and twist rn because about 8-9 days ago, about 5 days into my prob, I hit them w half suggested strength calmag and half recommended grow big by ff. ( which I know now is a no no. They're looking a bit better today. I will continue to keep my eye on everyone suggestions and experience and just try and listen to my girls. Thanks everyone

Glad it's getting better! Heres two rules that might help going forward:

1) always check everything that you pour in just before you pour it (pH & ppm)

2) calibrate your pH meter often

Good luck!