Please help! Possible Mg Def can anyone confirm?

[hoods1975]

Hi all,
I am at the end of my 4th week from switch and some fan leaves at the top and middle are starting to yellow.
I think it's Mg def and would be real grateful for a professional to confirm this.
Another issue could be my water being 0.8 EC and PH 7.1 out of the tap, so I'm going to start using bottled water with EC=0 PH 6.4.
I've heard about the Epsom salts but not sure how much per litre.

The strain is Great White Shark (GH) in loose rockwool (hand watered).
My nutes are Canna Aqua and i half the dosage they say on the bottle and that brings me to EC 1.8 (inc 0.8) PH'd to 5.7.
So i'm not sure if the feed is too strong.
Temps are a steady 78-80 (600 HPS) and RH 40%.The water is at 21 degs before i hand water them and i have been leaving the pots to dry out a bit (5 days) before the next feed.
Thanks for your time and peace to all.
Here are some pics
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[Ganja Guerrilla]

you have several defeciencies


as I understand it your watering with corrected to 5.7ph,

what is the runoff ph

[Hashmouf]

Originally Posted by Ganja Guerrilla

you have several defeciencies


as I understand it your watering with corrected to 5.7ph,

what is the runoff ph

Yes it looks as if you have a few defeciencies on you hands. when you grow in soiless mediums it is very crucial to remember to supply Trace nutrients.

[GrowBot]

the dosage for epsom salt is 1 tsp. per gallon of water. why are you feeding at half strength? your water temp. is 21 degrees? that's below freezing! what are you giving them, ice cubes??? you can't wait 5 days to feed/water in rockwool. most folks water several times a day. it's hydro, you should be feeding them every day. you might want to read some stickies.

[Ganja Guerrilla]

what are you giving them, ice cubes???

priceless

[hoods1975]

Thanks for the input people.

I do know enough not to give plants freezing water.
When i say 21 degrees thats f not c.
As for the half strength nutes - the reason for that is because at full strength i have had burning of the leaves.
The medium is granulated 1cm loose rockwool (80% water 20% air).
The water holds for ages in this medium and had no probs what so ever during veg.
In fact its the fastest I've seen so far.
The drainage is superb and no worry of drowning your plants.
I have a White Shark mother in a 20 litre bucket and have been feeding her every 7 days and she is looking and growing how she should.
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These defs are since they have been getting bloom nutes (2 weeks).
If there are several defs then can anyone tell me what they are.
Thanks for your time folks
Peace

[GrowBot]

no worries hood, i knew what you meant, just effing with ya. here's auggestion. increaase feeding to once a day for 3 days and see what happens. i'd bet a shiny nickel your problems fade. when your ph is correct and you have a def. increase the def. element. i.e. more frequent feeding. remember, you're in hydro. hydro should have access to food at all times. the rockwool won't hold on to food like soil.

[hoods1975]

Thanks growbot i'm gonna do that as from today and see what happens.
I'm in no way dissin your advice dude and really grateful for the reply.
I'll keep you posted.
Thanks again
Peace

[hoods1975]

Hey guys
I am growing in loose rockwool cubes (1cm) and using single pass system to feed.
I flushed my plants yesterday with tap water=0.8ec and adjusted the ph to 5.5.
I have added some bloom nutes today=2.3ec and ph 5.5.
i have 11ltr wilma pots and added 3ltrs to each pot and got loads of runoff, after measuring the runoff it was 0.9ec and 5.9 ph.
My question is does my runoff have to be the same as the juice going in or near to it.
If thats the case i've got alot of nutes to mix.
Any help would be great
Thanks all
Peace

[GrowBot]

don't chase ph. adjust your ph to what is suggested and go from there. personally, i think 5.8 is better but that's me. when you water/feed, do you allow for any runoff? this acts as a mini-flush and eliminates the need to flush. if you ph everything you put in/on your plants, then ph should never be an issue.