My first indoor grow

That kind of stuff is more about what a light can actually 'put out'...if you can, download the phone app Photone, from there you'll need to buy (but really cheap at 6.99$) the profile for the type of light you're working with. That will tell you the PPFD and DLI readings you're getting at the level of the top of the plants. Seedlings want something like 200-300PPFD (MuMols) and once you get them a bit bigger you're looking at 300-600 in veg and then 500-1000 for flower. Raise or lower your lights to achieve these readings.

Ola amigo tudo bem? Isso esta a queimar nutrientes. Mas nada assim muito preocupante pois parece que esta no inicio. Deves fazer um flush nas plantas que estão assim e depois quando fores regar uma boa dose com ph bem regulado. Podes não regar com nutrientes sempre, podes alternar isso apenas com agua. Boa sorte no cultivo

It is a good possibility. Your fan shouldn't be blowing directly on the plant.