Any ideas what this is?

Red Hard Head said:

Looks like a necrotic spot coinciding with the nutrient deficiency. Potassium and calcium deficiency can cause

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Yeah I have been worrying about that necrosis thing in the back of my mind a lot recently, I was told that if it happens I need to feed until run off twice a day. And my coco is getting pretty dry now after 24 hours.

Red Hard Head said:

Looks like a necrotic spot coinciding with the nutrient deficiency. Potassium and calcium deficiency can cause

Click to expand...

So should I get some Canna Cal-mag to treat it?

harrychilds said:

Yeah I have been worrying about that necrosis thing in the back of my mind a lot recently, I was told that if it happens I need to feed until run off twice a day. And my coco is getting pretty dry now after 24 hours.

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Get some yucca sm90 or other surfactant to help wet the whole media. Identify the deficiency first. There's a few you got, probably under fed. But yeah likely cal mag will help and not cause harm.

Red Hard Head said:

Get some yucca sm90 or other surfactant to help wet the whole media. Identify the deficiency first. There's a few you got, probably under fed. But yeah likely cal mag will help and not cause harm.

Click to expand...

I have never heard of yucca sm90 before, I am learning new stuff everyday and I love it. When I feed them I am just banging two liters of feed in until I get run off, (PH 6.0) (E.C 1.6) am I feeding too fast and the coco isn't absorbing the liquid?

Very possible. Wet the medium with water before feeds. A wet paper towel spreads an ink drop further than a dry paper towel right? I give feeds in pots slowly especially if they dry out quickly. And not all at once. Feed/ water wait, feed/water wait.