Would the wrong ph make my leaves "claw" and go leathery?

I have 9 plants.
1 x vintage 2006
1 x purple haze
1 x critical
6 x holy grail kush
The problem I'm having is with the 6 holy grail the other 3 look perfectly healthy. The leaves have started curling under or clawing and have turned dark green and leathery and 2 of them are way behind the others with slow growth.
They sprouted through from seeds 3 weeks ago and have just been giving them water from the tap after leaving it out for 3-4 days to let the chlorine evaporate 1st but don't have a ph tester yet so was thinking the ph might be too high and if this would cause the problem? I started them off on a half strength nute solution last week and have been feeding them 200ml solution every day is this too much?
They are now starting the 4th week of veg, 1st 2 weeks just water last week half strength nute solution. They have 6 nodes now but are still short and are not stretching much the 2 that are behind only have 4 and they 2 are the ones with the worst curled in leaves of the 6.
Growing in canna soil 11l pots
600w sunmaster dual spectrum light on 24/0 temp around 25c degrees all the time 50cm from plants
Dutch pro nutes
Getting a ph tester in next few days as I think this has a lot to do with it but hey I'm far from being a botanist lol any advice would be great

can u post a pic?

Not sure how to I'm on a iphone

Is there a way to post the photo from my iPhone?

Just had the exact same problem. So I checked the run off of one of my girls. The ph was 4.5-5 and very merky...soooooo I flushed them all with ph'd water to 6.0. Added no nutes, just ph'd water.....flushed 3 gallon pots with 10 gallons of water, checking the run off every so often until it was running out 6.0 and crystal clear. After of course they look droppy but in a matter of 2 hours...they never looked so happy.

It took me 4.5 hours to flush 12 girls and get them happy. The leather look is a ph problem.
5.8 to 6.2 will be good for soil-less

View attachment 2494040
They are 35 days old from seed....5 days into flower

just buy a $6....ph drop test....that's all u need

Yes you are feeding them way to much.....Feed wait 3-4 days, then water only (ph'd), 3-4 days feed, etc, etc.....

sounds like you're defiantly feeding too much. dark green claw is nitrogen overdose and is irreversible to affected leaves.
flush the plants well with plain water next time you water. then resume feeding way lighter then you previously were especially on the most affected plants. either them holy grail kush are real nute sensitive or you're other plants are on the verge of overfeeding also so id be going easy on the feeding schedule of all you're plants. that's my opinion

idealy post pics of the overfed and the healthy plants

Chez81 said:

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Yup flush right away and forget about them for a few days they'll be fine!!!!!

first 3 pics are of the clawing/curling leathery feel, 4th pic is the size difference as they sprouted same time and are the same age fed exactly the same and last pic is of the healthy ones also fed the same way in same tent as others

flush with ph7 water in soil. them hgk must be way nute sensitive the others don't really look overfed but id cut back to 1/4 strength nuts for a feeding or 2 just to make sure.

are the grow lights on in thoughs pics? kind of looks like the start of a mg def on a couple of leaves of the healthier plant pic but could just be the lighting. is it slightly yellowing in between the leaf veins?

ok ill wait till i get my ph tester in next few days or borrow a mates before i flush, that way ill be flushing with ph'd water and then leave the soil to totaly dry out. After that should i mix a half strength solution and ph test that before the next nute feed?
Will the curling leatheryness heal or will it stay the same but new growth come through ok? should i wait till the plant is a bit bigger then remove the affected leaves as they will be near the bottom of the plant anyway or just leave them on?

the bent botanist said:

flush with ph7 water in soil. them hgk must be way nute sensitive the others don't really look overfed but id cut back to 1/4 strength nuts for a feeding or 2 just to make sure.

are the grow lights on in thoughs pics? kind of looks like the start of a mg def on a couple of leaves of the healthier plant pic but could just be the lighting. is it slightly yellowing in between the leaf veins?

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yeah the light was on when i took the pic thats why they look yellowish but they are absolutely fine and look a nice lush green when you look in normal light

no nutes...see how they react to the water (no sure if canna is soil or soil-less, if it is soilless ph around 5.8-6.0) ..file://localhost/Users/Pook/Desktop/PHRANGECHART_zpsddd4a5c5.gif

ph you water AFTER you add your nutes.......always...

here this might help you with your ph problems and what you can look out with the wrong ph.
View attachment 2494069

as you can see 6.5 for soil is the best for allowing all nutes

Dirty9mm said:

no nutes...see how they react to the water (no sure if canna is soil or soil-less, if it is soilless ph around 5.8-6.0) ..file://localhost/Users/Pook/Desktop/PHRANGECHART_zpsddd4a5c5.gif

ph you water AFTER you add your nutes.......always...

here this might help you with your ph problems and what you can look out with the wrong ph.
View attachment 2494069

as you can see 6.5 for soil is the best for allowing all nutes

Click to expand...

so add the nutes then ph test the solution and adjust to 6.5 thanks for the advice.
Will the plants heal or will the affected leaves always stay like that now?

Those leaves are toast, it's the new growth you want to watch....yes ph AFTER nutes are added.....i found the nutes lower ph......After you flush I am interested in knowing the ph of your run off....just for my own knowledge...in case my plants every look like yours I'll know exactly what to do...thank

Dirty9mm said:

Those leaves are toast, it's the new growth you want to watch....yes ph AFTER nutes are added.....i found the nutes lower ph......After you flush I am interested in knowing the ph of your run off....just for my own knowledge...in case my plants every look like yours I'll know exactly what to do...thank

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yeah when i flush ill post what ph the run off was thanks.

so what ph should my flush water be? 7 or 6.5?
they are in soil

well i have just flushed my 11l pots with 40 litres of ph water ph'd to 6.5.
my runoff was coming out at 5.7. The runoff now is around 6.4 now so should see a great improvement over the next week with the new growth.

yes you should, what was the initial run off of your water before you started flushing? 5.7?

Curling under/down, dark green, clawing is almost always over-feeding and/or over-watering.

And get a real pH tester. A good one is Oakton eco testr for about 60 bucks. Amazon or Ebay. Test water/fed going in and runoff coming out until you master your soil pH.