HELP, tiny yellow dots on leaves over night?

I have 2 Gold Leaf plants about 2 months old. They are side by side in a tent and were put into flower on July 5, under a Electric Sky 300 watt. Growing in CoCo and perlite. Using Advances Nutrients, 3 part with added Cal-Mag. PH good and 800PPM. They where both green and healthy yesterday and this mourning ONE plant has tiny yellow dots on a lot of the Fan leaves. Just dots , no yellow or brown tips. The other seems fine at the moment so I think it cannot be bugs since only one affected. I have checked leaves for bugs with a microscope but I see nothing… I also noticed that the leaves on some of the affected leaves shriveled up fast once picked. I am using a cheap 60X loop, is that big enough to see bugs if that were the problem. Thanks in advance.

That’s plenty magnification to see bugs. Tiny yellow dots could be calcium deficiency. White dots are usually bugs. Got any pics?

Have pics but dont know how to post them. Please check back later while I find out how to post pics. Thank you for your time.

Here is one leaf

Hmmm that does look bug related. Especially if it happened overnight. Is this a pic of your plant or just a pic of what it looks like?

Pic of what it looks like, but it is exact. Happened over nite but I have looked for bugs on numerous leaves and nothing. to see. should I be able to see any bug?

Also, you should know the 2 plants are under same screen and one is perfect

I think it is the beginning of a calcium deficiency. Not 100%

(100% sure its not bug related though)

Thanks, Have been adding calmag, and about the same to both plants since they are in coco.

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I have had the same happen when I grew in soil. I had root aphids, that’s why I switched to coco but since you already grow in coco not sure

Thanks for your reply. Right or wrong , I removed all the leaves with dots, gave extra Calcium and it seems to be OK. It has been a few days since I noticed that the dots appeared over night. I have 2 Gold Leaf and 2 Super Skunk and am not sure who is who. So maybe the 2, that I think are both Gold Leaf may not be and they may have different needs when it comes to Fert and Calcium since the 2 get the same amounts. I also moved the light higher since it was mainly top leaves affected. So maybe it was an Calcium Defiency. Thanks everyone.