Can anyone help? Yellowing leaves 1 week into bloom.

Can anyone help me?I'm getting yellowing leaves 1 week into flowering. I have a few diffrent strains but only seems to be a few that are getting the yellowing.
I'm growing in 15L Air pots a with a 60/40 coco mix, with canna A&B. My PH is running about 5.6/5.8 and my EC 1.3/1.5
I have a little tip burn starting at the ends, so this is making me think I'm starting to over fert but the yellowing in the center is confusing me. I was thinking it was the PH but that seems to be fine. Can over heating do this? i have Co2 running as well so i would think they could handle i little more heat and more nutes than I'm giving them. Also these are mostly new leaves not old ones.
to much nutes but not enough something I'm guessing also i'm getting leaf curling under like a claw shape, i think this is over heating? or not enough air? but i have put Co2 in and the air flow is quite good.

I'm not sure whats going any more, What am i missing??

Take a picture without the HPS light on, no one can tell anything since the lighting makes everything look yellow.

Sounds like you have a N def starting, but clearer pictures are needed.

how high above the canopy is your light and what watts? looks like heat stress to me, or maybe iron def. im pretty sure that nitrogen def starts with the lower fan leaves and works its way up, new growth normally appears a bit yellower or lighter green. just my two cents

I know, I just thought I would stick something up on the post till my lights go out. I'll post some more up tonight.

Is your water RO? If so have you added cal/mag to compensate for the RO water? Is nitrogen lock out possible due to somewhat low PH? Just throwing that up there, too lazy to find my chart. lol

I think the curling is heat but I'm not sure, I did have a little heat problem but it's looking ok now. I have 3, 600w, HPS just over 12" away from the tops.
It's not nitrogen I'm sure. After a closer look I can see it's on new and old growth. IT looks to me like PH so I checked my run off and it's way to high at 6.8 some at 7.3. I've no idea how it got this high, I'm going to give them a flush with ph of 5.7 and see if they look any better and I will post clearer photos tonight for a better look.

RO water?, it's soft I'm sure and I leave it 24hours after it comes out the tap before I use it.

Whats the ppm of your tap water before any nutes are added?
It looks like mg def to me, coco usually needs calmag anyway but some strains are mg hogs so will show deficiency sooner than others.

The ppm of my water is 0, you would be hard pushed to get cleaner.
Why would my PH run off be 7 if I'm putting 5.6 in.
Here are some better photos.

Fuzzology said:

The ppm of my water is 0, you would be hard pushed to get cleaner.

Click to expand...

If your start water ppm is 0 then you need to add calmag to it until it is 250ppm then add your canna a&b to bring it to your feed level. You need calcium in the water to keep the ph buffered thats why it is changing.
Get some calmag and your plants will thank you for it

Make sure you run this through the coco until you get plenty of run off the first time and do it again the second time you feed.

Also what are you mixing with the coco in your 60/40 mix?

Thanking you, I'll get some tomorrow. What would you say the curling is? the same thing or could that be over heating?

1.3 is not that high but with ph levels all over the place then you probably have some lockout.
I'd probably mix the nutes to 1.0 ec and flush that through them thoroughly.

What brand of coco did you use?

it looks like a little over fert to me. 1.5+ seems really high to me although I'm not familiar with that line. the leaves are clawing a bit which would make me think too much n. salt buildup in coco can definately lock out some nutes. personaly i try not to let my coco runoff get over 1.4 ec or so. I realy never feed too much higher than 1 ec, but i use a different nute line. hth and gl

With canna nutes i'm feeding at 1.7 ec at the beginning of flowering and that will rise to 2.0 by mid flowering although some of that is made up of calmag and silica.

It's gold leaf 60/40 out a bag, I give them Cana A&B, liquid bat guano(liquid), silicone, Rizotonic, canazyene, I will give them boost and Pk 13/14 a bit later.
I normally use cana coco and mix perlite and bat guano through it and a bit of super thrive( just for luck lol) but it was just easier for me to try it this way this time.
It's the Chocolope that are being hit the hardest with it, the other ones cotton candy, sensi star and super silver haze seem to be handling it a bit better.
I have also ran as high as 2.0EC in the past with Co2 and not had many problems but i was stumped at what was going on here.
2nd pic was a few days ago.