nuit burn of perhaps deficiency or temp low PH

anyone know what is happen with these.?
hydro setup -medium – hydroton 100% nothing else
10 days old
Nuits - 50ml canna a+b - 100ml rhiztonic Ppm 700
Res ph 5.5 (calibrated) in clean res. 1 day old – // [[tap water (pre-nutes/ph levelled) = ph 8.6 / 0 ppm]]
temp 22c to 29c
light 600w hps 3 feet from plants

doing fine until 48 hours ago
edges curling up and losing all colour (white / light yellow). some other leaves not doing that but are drooping

more developed plants seem worst hit rather than younger smaller plants (though tell tale signs of this starting is showing) old leaves hit by it first
it can been seen to start on the smaller plants with ever so slight discoloration of tips and ever so slight curl upwards at end

checking ph getting 5.5 though was needing recalibrated and it was really 4.25
recalibrated the reader and added 0.45 ml ph up (42 ltr tank) ph now 5.53 and is correct. (just before taking pics)

UPDATE
Added another 20 lts water to lower the ppm to almost ½ to 400ppm ph 5.6

Not seeing improvement – younger plants and smaller leaves now showing signs of yellow edges:
SEE NEW PICS - taken with different lights (not hps)

i am not a hydro grower but even 400ppm is on the very high side of nutr for those seedlings.

due to the low pf and high salt content the plants are shocked,probably pushed by too much N but couldnt get the needed amount of cal-mag.

less is better when plants are that small.

thanks for the reply,i was wondering if i would get one.

i have lowered the ppm to 400 by adding more water to the res, i will add more water to lower it still and see how it goes.

they look like they are getting worse, so i will do this right away

would 200ppm be the right amount, considering they have no soil at all just hydroton which as a medium have nothing for the plants to grow in

thanks for the feed back

Drop your nutrient strength you're getting a little burn. 400 ppm should be pretty mild but watch new growth for burning the old stuff will never heal but if it gets worse use less nutrients.

NewGrowth said:

Drop your nutrient strength you're getting a little burn. 400 ppm should be pretty mild but watch new growth for burning the old stuff will never heal but if it gets worse use less nutrients.

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thanks for the input. everything was going fine untit late. was on 200ppm but i thought they might be at a stage where i could increase the ppm.it was the oldest most developed plant that got it first so i flush a redid res. but added more nuits as i thought it was a nuit deficancy.

any and all comments welcome =)

up the nutes by 50 or 70ppms max every feeding. like 200-250-300 or 200-270-340 etc..

by going from 200 to 400 your doubling the nutes what the plants may not be able to take.

do you think that is a 'little'nuit burn... it looks like a lot to me. i have brought ppm down to 300 and 24 hours later here are pics .(before i brought the ppm down).remeber there is no soil,rockwool etc just pure hydrotron only .i dont want the roots to dry out so i water alot, so they getting a lot from the res. even at the 400 - 300 ppm level .my tap water ph is 8.4 ish and full of cal. so i dont know if flushing/watering with this is better or worse..l not sure what to do.

from 100% healthy to this in 24 hours

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This plant has gone for 100% healthy to this in 48 hours after new res with more nuits. 50ml nuits from 30ml nuits originaly + 100ml rhotitonic (to help the roots) and replanted from peat to hydroton.

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i think above pic,leaves with yellow spotsid due to spilling res. water on when hand watering and getting leaves wet(burn from heat with nuit-water splashed on) would this fact alone mean that the rest of plants having nuit burn, or does not matter as is the it the same with baby and fully grown plants when it comes to burn on leaves to due nuited water?

congoz said:

up the nutes by 50 or 70ppms max every feeding. like 200-250-300 or 200-270-340 etc..

by going from 200 to 400 your doubling the nutes what the plants may not be able to take.

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my reader is not that acurate. only 100ppm at time. you say 200-250-300 and so on but i am using cana a +b and instructions are german, i know you have to add the same of each.says76ml for a 42lt tank but most folk say only use a 1/4 of that to start of plants and developed

Make a choice based on available information; watch, and learn.

you have much knowledge , oh wise one. reductions in place, time will tell