Discolouration in new growth, young plants

Hi all,

New around here, been searching everywhere to try and find photos similar to what my plants are looking like but struggling to figure it out myself. Ima first time grower and so far so good, however I think I’m coming across what I think are my first deficiencies in the plants. Tbh it might just be me, but I’m determined to try and get it right as much as I can.

New growth is light in colour, which doesn’t seem quite right... most things I read say it will be moving up the plant rather than starting at the top. I’ll post photos of all 3 under normal light and under my 400w mh (it makes it easier to notice imo) my first thoughts are lack of N and mag but old leaves look green (I burnt my seedling so I tapered back on my feeding, nooby error) leaves look happy after lights on period (should be first photo leaves praying a little) I’m just worried about the discolouration.

Here’s some info to help the situation;

fast buds galato auto / day 19
coco perlite 70/30 mix
16L fabric pots
Transplanted 4 days ago from solo cups no obvious shock

watering everyday with nutes 1200ml ~30% run off each plant
nutes;
RO water - PPM 260 / Ph 5.8
Cal mag 0.8ml/l
Canna coco a/b 0.8ml/l (just uped a day ago from 0.4ml/l)
Cannazym 0.6ml/l
Rhizotonic 1ml/l

400w Mh 16 inch from tops, air cooled hood
Temps lights on at tops 24-25c (tent about 22-23c)
Temps lights off 20-21c
Humidity 65-70%
good airflow with breeze rustling leaves (very light barely moving)

Anymore info I can give I’ll try my best to get it too ya, to anyone who posts thanks for the help! Much appreciated.

Thanks VT

Looks like it might be slight Zinc deficiency.

Since you've just upped your nutrients by 100%, I'd highly recommend giving it at least a couple of waterings before changing anything else. You need to figure out if the change you made has any effect. If you change something else now, you'll never know for sure what fixed, or made worse any issues.

Agree....looks like you are having a zinc def. Water with normal tap water and that usually has more then enough to get her back on track,

my tap water ppm is 350 would you recommend still? would a zinc product be a better option? Reading the back of canna a+b it has zinc in it, I was putting the bare minimum of both in after burning so do you think It might clear up now I’ve increased the dose (think I should wait a day or so like spek9 said) I’ll keep an eye on them and will try add a little tap water in with the RO maybe if I see no improvements, thanks

Have you pulled them out of the tent and looked at them? My plants look very light green in the tent but appear super healthy outside the tent, especially in photo's.

The 3 photos in natural light are out of tent, they look a lot better for sure but you really see the difference inside, definitely makes it look worse under the mh bulb. I’m reading into zinc now, I overlooked it because they’re young but I think the guys are right, articles mention problems with RO water. The leaves are nice and perky just discoloured, hope to get it under control again