Magnesium deficiency?

Hiya,
This is a FastBuds strawberry banana auto under an enhanced spectrum QB288 in DWC. PPM is about 700 and ph 6 - 6.5. Very obvious yellowing of leaf tips, to em it looks like Mag deficiency, do you agree? Ive been feeding her epsom salts but perhaps i need to give her more?
Any thoughts?
Thanks!

Looks more like light stress to me..

Doesn't look like mag def.. Looks more like light burn.. Is it happening lower on the plant?

HydoDan said:

Doesn't look like mag def.. Looks more like light burn.. Is it happening lower on the plant?

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Its definitely on the upper parts of the plant. IR thermometer reads about 74° at canopy, is that enough to cause light burn? That part in the picture is about 40cm from the light.

Light stress comes from the plant getting more light than it can process..
Heat stress comes from high temps.. You can get light stress at any temp..

HydoDan said:

Light stress comes from the plant getting more light than it can process..
Heat stress comes from high temps.. You can get light stress at any temp..

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Ok cheers Dan my MW driver is adjustable so I'll reduce it see how she does cheers

mag deficency starts at bottom and its yellow but veins are still dark.
how far is the light? got the ppfd app?

amneziaHaze said:

mag deficency starts at bottom and its yellow but veins are still dark.
how far is the light? got the ppfd app?

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Light is about 35cm from canopy no i dont have the ppfd app is it any good?

shiva71 said:

Light is about 35cm from canopy no i dont have the ppfd app is it any good?

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depends on the phone some have a really low high value limit. but they have a nice accuracy

Raised the lights and dimmed them but seems to be getting worse. Yellow tips everywhere

The affected leaf tips won't really recover all the way, and it might take a few days or a week for the plant to re-adjust. Light stress and heat stress are 2 different conditions, but sometimes go hand in hand. Keep an eye on the new and upper growth that it isn't preying to escape the light, or twisting, bleaching etc., and don't expect overnight results. There's a hot (bright) spot under your panel, and it for sure looks like stress. Otherwise they look good, and you aren't really pushing the EC too high.. so yeah.. Would be better if the panel was more spread out for even coverage. Otherwise you gotta do what you gotta do, and raise it up more if you have to. You might even want the canopy to get a little bit warmer using LEDs (75+), which seems like a backwards approach when dealing with light stress, but leaf temps during the day are important to how well the plant transpires, and transports mobile nutrients, etc.

shiva71 said:

Raised the lights and dimmed them but seems to be getting worse. Yellow tips everywhere

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At the beginning it definatly wasn't magnesium deficiency.

You have too much nitrogen, the overly green look and tips curling down.
Yellowing of the leaf tips and margins is a a sign of potassium deficiency, which you have made worse if you have been adding calcium or magnesium since they compete with each other.

Ratios around 4:2:1 for K:Ca:Mg could be used as starting point depending on growth phase.

Hey doods thanks so much for the help - probably my 8th grow but still keep having issues!!
Ok so noone things its Mg deficiency. Overnight ppm went from 850 to 900 so i guess nute burn is also a possibility. Ph also went up from 6.3 to 6.7. I have 3 of the same strain they all seemed happy about 750ppm but i kept trying to throw more at them and none have liked it.
Topped up the rez gave her one part of Canna Hydro Vega which is 0-3-4 cus yeah probably some N issues and a bit of calmag. 750 but with the ph down 780.
Also something i noticed some of the tips are curling up

Lights raised and dimmed, heres the whole plant this morning, i mean shes not looking so terrible i hope with the lower ppm and raised lights shell pull through...cheers guys!

If your ec and ph are rising you need to lower your ec.
I'd do a res change as a precaution.

There's a chart if you Google ec ph fluctuation chart

coreywebster said:

If your ec and ph are rising you need to lower your ec.
I'd do a res change as a precaution.

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Thanks yeah i lowered it to 750 these issues started when i was putting her over 800. If it goes up again ill drop it further.

shiva71 said:

Thanks yeah i lowered it to 750 these issues started when i was putting her over 800. If it goes up again ill drop it further.

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What ppm scale are you using ?
What does it equate to in EC?

coreywebster said:

What ppm scale are you using ?
What does it equate to in EC?

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Ummm...haha you ain't gonna like this, I don't know what scale, it's whatever my Milwaukee probe is set at. And in some ways it doesn't really matter, if the reading (whatever scale it is) goes up, then the plants not feeding and it needs to be lowered; if it goes up she is feeding and it can be raised slowly. I just work on those principles. I calibrate it with 1413 solution and I know my tap water is about 170ppm these are my references.