I'm super disappointed in these seeds and after more research it appears they are junk. I have about a dozen autoflower grows under my belt and this is by far the most disappointing. I purchased these seeds from Pacific Seed Bank and it appears this company is a scam. The breeder is supposed to be Advanced Genetics but I'm unable to find any information about them. I will likely be pulling them and starting some Fast Buds orange sherbert seeds. This has cost me a alot of time and money.
Don't worry, next yeld will be great. It's probably as you say. That's why it's worth buying from well-known and reputable seed banks!
Btw. why so much of sand? Inside also? Looks not so good for plants.
Best regards!