Solil grow, plant problems Magnesium def ?? Plz Help

Hello.. I am at week 4 of flower right now, PH 5,9 - 6,2 I am using advanced hydroponics 3 part nutrient system (bio, grow and bloom) I am following the instructions on the bottle fully. Temp. is 27-28 degrees Celcius, RH is kept at 40% All in all my grow is looking quite good
BUT these last few days 2-3 of my plants have been getting dark spots on the leafs, and lower leafs are drying up a bit. I have flushed these plants with LOTS of water, but is hasn't helped.. What can this be? Someone told me it could me Magnesium deficiency.

Pics included above.. Please help?

Looks like a magnesium deficiency. Some calmag or microblast would help. Are you using R/O water?

Are you using Grow, MICRO and Bloom? If your using Micro surely it contains magnesium?

cowboylogic said:

Looks like a magnesium deficiency. Some calmag or microblast would help. Are you using R/O water?

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No I'm using regular tap water, and it should be mentioned that I live in an area with hard water (I'm from Denmark) water is 400 ppm (mostly calcium)

what about pure magnesium additive, thats the only thing I can get in my region?

Harrekin said:

Are you using Grow, MICRO and Bloom? If your using Micro surely it contains magnesium?

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Yes I'm using it as perscriped on the bottles.. (½ strength for soil, it says)

epsom salt

you should be using a hard water micro also. if you are not already.

wiseguy316 said:

you should be using a hard water micro also. if you are not already.

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That might be the problem, because it's not (it doesn't say on the bottle anyway)

I'll get that first thing tomorrow morning..

Too much calcium is probaly causing some lockout issues. May even being messing with your ph some..........

don't forget the epsom salt, mg sulfate

cowboylogic said:

Too much calcium is probaly causing some lockout issues. May even being messing with your ph some..........

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I test my run off water often, PH i spot on.. It must be the calcium lockinng out the magesium in the mix..

wiseguy316 said:

epsom salt

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I use this, but what dosage is best?