deficiency / toxicity issue?

Hi All, was hoping to post a few pictures of issues I'm having in hopes some more knowledgeable people (pretty much everyone) may be able to assist me. My current setup is:

Hardware:
4x4 tent
SF4000 LED light 18/6
exhaust fan for air exchanges
2 fans for air circulation
dehumidifier to keep RH down (RH ~50%, Temp ~70)
Exhale 365 CO2 bag

Nutrients:
Fox Farm Trio (Big Bloom, Grow Big, Tiger Bloom) - ~1/2 of recommended dose from their chart (~800 TDS using a TDS meter that uses a .5 scale). doing Feed, Feed, Feed, Water
Botanicare Cal-Mag - 5ML/gallon every time soil gets wet
RO water, (plants watered or fed depending on which time it is every 3 days). Ph'd to range of 6.2

Medium:
5 gallon fabric air pots on raised stands.
Promix BX amended with 2 Tbs/gallon of medium of dolomite lime.

Seeds:
Seedsman Northern Lights Fem Auto

Stage:
I'm on day 71, and have entered the early stages of flower. I know a few other people on here have grown this strain (@Gentlemencorpse for one). I did a flush on day 43. I'm sort of leaning towards a Phosphorus toxicity which is locking out Cal/Mag/Zinc/Iron. My run off PH is high 5's low 6's. with my input PPM being 800-900 and my runoff right around 1,100-1,200. I had originally thought they were nutrient deficient because I was only doing FF at a lower dose but based on my elevated run off I'm thinking I may be overdoing it? I know everyone says you have to adjust your feedings based on how your plants look and I've been trying, however, it's my first grow and while I've been searching the internet and forums for pictures and advise, as a new grower they all look very similar. I recently ordered some Mega Crop and was thinking of switching over to that after I do another flush to sort of reset. Does anyone have any thoughts on a mid grow nutrient line switch? Any advise or comments on my pictures or if I can provide any additional details on my grow or other pictures please let me know. Thanks very much for anyone taking the time to read this and offer any advise!

What's the pH of your nutrient solution going in?

To be honest I found the NL auto to be extremely nute sensitive. Mine looked just like that after a while, and nothing I tried stopped it from spreading. The buds filled in just fine anyways so at a certain point I just said screw it. In general I find autos to be way more of a pain in the ass to get dialed in.

I think you'll like the MegaCrop though. Dry nutes are much easier to use in my opinion.

Thanks very much for replying, I was hoping you would! I value your experience immensely. PH in is around 6.2, usually varying 6 to 6.4. I was sort of thinking that it doesn’t appear to be spreading too quickly so I’m hoping to outpace the spread with the buds maturing. Awesome, I’m excited to try MegaCrop. My next grow will be Cinderella XX from Brothers Grimm with MegaCrop so hopefully moving away from liquid nuts and go to a photo period will give me a better experience. Thanks again!

Yeah, it's hard to say what's going on then. Root zone pH may be a little low but it doesn't sound like it's too far off. Probably just have nutrient salts building up in the medium. Just guessing since your runoff pH is much lower than your nutrient mix while your PPM is higher. Suggests the medium is saturated with nutrients. I'd keep using just ph'ed water until the runoff PPM drops a bit myself. This happened to me on my last grow because I was trying out bottled nutes again. That's the last time. I'm sampling Veg and Bloom Dirty on some plants right now, which is similar to MegaCrop. Never had an issue with dry nutes. Also messing with some super soil mixes.

Funny enough I just dropped a Brother's Grimm Cinderella XX in my 1 gallon SOG grow. Really nice smoke.

Awesome, that's sort of what I was thinking. PH'd water, until PPM's drop down a bit and run off PH hopefully comes up a bit. I think i'm done with bottle nutes as well, assuming I have some better success with MegaCrop. That's very funny. A friend of mine introduced me to C99, and I was very impressed. So impressed, decided to make that my next grow (or at least the feminized version CXX). I've heard really good things about the speed and yield of the Cinderella XX, so pair that with the quality of a very solid smoke and I'm pretty excited.

You just have to water in between feedings. Some people forget this or skip it to try and fix things.

I agree with that assessment, I had started off doing a Feed, Water, Feed, Water at 1/2 of what FF recommended and I noticed some N deficiencies on the lower leaves and I think I over compensated with Feed, Feed, Feed, Water schedule. I was probably very mildly under feeding and cranked it up too much. I really appreciate the input Wattzzup!

Jerry Tyson said:

I agree with that assessment, I had started off doing a Feed, Water, Feed, Water at 1/2 of what FF recommended and I noticed some N deficiencies on the lower leaves and I think I over compensated with Feed, Feed, Feed, Water schedule. I was probably very mildly under feeding and cranked it up too much. I really appreciate the input Wattzzup!

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We’ve all been there

How far away is the light?
I checked the data sheet for the promix bx and it already has lime in it. The bx has a pH of 5.5 - 6.5. No need to pH really as the soil buffers it.
Maybe you are over feeding them. They're autos and you are feeding them 800 ppm which is 1.6 ec to me. That's a strong feed for my photos and they say autos need less.

Light is ~16" or so from the canopy. Yes, I agree with your Promix BX comment. I had an issue early on where my 6.0 PH'd input water was resulting in a low 5 run off. A lot of the people running BX comment they add slow dissolving dolomite lime to buffer the PH either with their original mix or top dressing as the grow goes since the lime starts to degrade over time. Promix BX is I believe more prevalently used among greenhouses that have shorter life cycle plants so I've heard adding extra can assist in the buffering. I 100% agree in light of some of the other comments and yours that I think it's probably pretty likely I'm shoving nutes down their throat and they don't like it. What ec or ppm would you generally recommend for an auto? I figured give or take 1/2 strength would be conservative enough (though my fault I also didn't stick to feed, water schedule), sort of another reason I'm going to give MegaCrop a try next round.

Jerry Tyson said:

Light is ~16" or so from the canopy. Yes, I agree with your Promix BX comment. I had an issue early on where my 6.0 PH'd input water was resulting in a low 5 run off. A lot of the people running BX comment they add slow dissolving dolomite lime to buffer the PH either with their original mix or top dressing as the grow goes since the lime starts to degrade over time. Promix BX is I believe more prevalently used among greenhouses that have shorter life cycle plants so I've heard adding extra can assist in the buffering. I 100% agree in light of some of the other comments and yours that I think it's probably pretty likely I'm shoving nutes down their throat and they don't like it. What ec or ppm would you generally recommend for an auto? I figured give or take 1/2 strength would be conservative enough (though my fault I also didn't stick to feed, water schedule), sort of another reason I'm going to give MegaCrop a try next round.

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This is why I check run off it lets me know what’s in the soil every watering. Water only until you see that ppm go down by itself. That means the plant is absorbing them.

That makes perfect sense, will proceed in that direction. Will give some updates as things progress. Thanks!

Jerry Tyson said:

Awesome, that's sort of what I was thinking. PH'd water, until PPM's drop down a bit and run off PH hopefully comes up a bit. I think i'm done with bottle nutes as well, assuming I have some better success with MegaCrop. That's very funny. A friend of mine introduced me to C99, and I was very impressed. So impressed, decided to make that my next grow (or at least the feminized version CXX). I've heard really good things about the speed and yield of the Cinderella XX, so pair that with the quality of a very solid smoke and I'm pretty excited.

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Unfortunately mine kind of missed the mark on yield ... it was the smallest of my 9 plants.

But the buds are nice and solid but still break up perfectly and the smell is stellar, like sap, sweet but piney! Nice stone too.

wow, those looks fantastic. Too bad on the yield, but I would still choose quality over quantity any day of the week. what was your grow schedule like in regards to veg time and flowering time? This is sort of sounding like i'm cheating, basically just growing everything you just finished

Nothing wrong there! That one was quick ... two week veg, 60 days in flower in a one gallon pot in soil. I got 15 grams off her. She was in a 32x32 tent under a 315CMH with 8 other plants.

Wow that's crazy quick and really maxing out the space. I will probably use the same 5 gallon fabric pots, 4 plants in my 4x4 and was thinking of doing 4-6 weeks veg depending on how large they get. I appreciate the information!