like I said I lean toward Magnesium deficiency with the red stems. Sounds like you are putting more than enough nutrients in. PH is a bit too high for coco. Maybe back off overall nutrients reducing K specifically and aiming for 5.5-5.6 PH. The phosphorus in PH down should help uptake magnesium...
4-20-39. This is what it looks like for ratios but I seem to fall short on mag at some point. I am in promix with added perlite. Struggle to keep runoff PH decent unless I buffer my RO.
My guess was the RO water stealing cal/mag to buffer PH. But either way I think they need more mag. I bet you would benefit significantly starting with a higher PH or adding some cal/mag or tap water to bring your ppm up to at least 80 before adding nutrients.
I run masterblend with RO and have to foliar spray epsom or add more mag in the soup to not be deficient. From what I understand LED needs more Mag never looked really into why..
Jack 321 does have cal/mag but it’s acting like a buffer in distilled water. Leave looks deficient. Calcium, Mag and maybe Nitrogen in my opinion. They make a jacks RO if you plan on continuing pure water.
I agree that they look fairly health. Under-watering will cause a spike in EC resulting in nutrient burn. Check your ph and ppm/ec of your runoff. They might only have 2 or 3 weeks left. I’ve read and noticed LED lights especially too close will tend to have a magnesium deficiency. Might be the...
I agree that flower nutrient profile isn’t necessarily necessary. It seems like you have to have more runoff to prevent the possibility of a lockout. I use master blend 4-18-39 combined with calcium nitrate and epsom salt. I also tweak the formula with MPK and magnesium nitrate as I see fit.
Yeah if it was K deficient adding more Mag and Cal will only compete more with the available K. You’ve probably seen these charts or a version of them by now but I’ll add them just in case. K/Cal/Mag should have a ration close to 3:2:1 in veg and pushed to 4:2:1 on or after the stretch. N/P/K is...
Do you test your EC/PPM and PH of runoff? Maybe slight N excess with the slight claw especially in the first plant. I think the deficiency looks like K which is harder to take up with high N.