I saw some white spot in the leave i do not know i...

Check under the leaves with a magnifying glass for mites and eggs. The mites will look blackbrown and they are very hard to spot. If you see any small spots..keep youre eye on it for a minute to see if it moves. The easiest way to check for them is to leave the plant undisturbed so they get a chance to make webs and then spray the plant with water from a fine mister. The water clings to the webs and makes them easier to see. As your plants are in flower... go easy if spraying them to avoid water affecting the buds in a detrimental way (bud rot). I would never reccommend spraying plants that are in flower, only if absolutley necessary or if you want to identify a problem. You've got many options if it is spidermites but whatever you choose, do it quick because their rate of reproduction is very high and they can devestate ur plant given the chance. If u have the cash and they are available, I would recommend introducing some natural predators of spider mites. If u can get hold of any ladybirds (ladybugs...whatever), they do a fantastic job of eating the spider mites and do no harm to the plant.

I had the same problem. Overwatering and the roots can’t breath thus cant take nutrients from the soil, is the soil really humid?

Nitrogen problem, perhaps a little calcium too. Tell me if you need more help

Watch very carefully for any insects/arachnids - if there's none, you problem is probably related to low humidity + bad air flow. Good luck with this baby !

I second @Athos opinion on this one.

I keep my room at 55% humidity during vegetation I read that it's the easiest at 60% for water to evaporate off a plant leaves and at 77°

looks like dried up water droplets to me. the water is likely collecting on the leaves and leaving water spots iwouldnt worry about it at all. have fun enjoy your grow

Hello m8 your strain look healthy to me.. don't worry much about does spots... it could be some stress from low humidity. In my opinion on veg stage you should have humidity in you tent about 50 to 60 %. It help moisture your plant. So best thing to do is buying one of those co2 bag and hang in side your tent. And this will sort the dry air flow that you have now on tent. Hope it could help. Happy growings 👌👌

Humidity been low might make your plants drink some more water, but it will not give you spots. Don't worry too much about low humidity during veg; as long as you are not spraying any chemicals on the air, there's no problem with it, if you want to do it to raise humidity. Ideally you want the pictures under white light, them been under purple led lights, make it difficult to see if the leaf color is ok. Anyway, what I can tell you is that you are feeding too early and are giving them too much water; for such young plants (I can count 3 fully open pair of serrated leaves and a budding 4th one), you should give them only water and only start feeding when you notice the lower leaves going paler; also 500 cc of water is what my seedling consumed every 5 days when at that stage and you are giving them that amount per day. As a new grower, over watering is your number 1 enemy, and it's the most probable cause for the symptoms you ware seeing right now.

Looks like the dreaded powdery mildew to me. Some neem oil should kill it. I’d also suggest lowering the humidity.